Cysts Of The Oral Region Pathology Question And Answers

Cysts Of The Oral Region Question And Answers

Question 1. Define a cyst.
Answer. Cyst is a pathological cavity containing flid, semifluid or gas, which is usually lined by epithelium and is not formed by the accumulation of pus.

Question 2. Why the cyst is called a pathological cavity?
Answer. In our body, there are many normal anatomical cavities, e.g. gall bladder, urinary bladder, plural cavity or pericardial cavity, etc. but these are not cysts in any way; because any cystic lesion in the body must arise as a result of some pathologic processes.

Read And Learn More: Oral Pathology Short Notes Question And Answers

Question 3. What are the possible contents of a cyst?
Answer. A cyst might have flid, semifluid or gas inside its cavity.

Question 4. Name some cysts which contain flid.
Answer.Dentigerous, radicular or globulomaxillary cyst, etc.

Question 5. Name a cysts which contains semiflid.
Answer.Odontogenic keratocyst (it is often filed with a thick, keratin-rich semiflid mass).

Question 6. Name some cysts, which contain gas.
Answer. Solitary bone cyst or aneurysmal bone cyst, etc. are usually filed with gas.

Question 7. What is a true cyst?
Answer. A cyst which has epithelial lining is called a true cyst.

Question 8. Give examples of few true cysts.
Answer.Dentigerous cyst, radicular cyst, and odontogenic keratocyst, etc.

Question 9. What is a false or pseudocyst?
Answer. A cyst which does not have epithelial lining is called a false cyst.

Question 10.Give examples of some false cyst.
Answer.Traumatic bone cyst, aneurysmal bone cyst and mucous extravasation cyst, etc.

Question 11. What is an abscess?
Answer.Abscess is localized collection of pus in the body.

Question 12. Does a cyst contain pus (pus is a viscous, yellowish-white flid formed in infected tissue, consisting of white blood cells, cellular debris, and necrotic tissues)?
Answer. Normally a cyst does not contain pus; however if it is secondarily infected there may be pus formation in the cyst.

Question 13. What is a cyst-abscess?
Answer. Abscess developing in a pre-existing cyst is known as “cyst-abscess”.

Question 14. Why the cystic lesions develop more frequently in the jawbones as compared to other bones?
Answer.

• Because of the typical embryology of facial skeleton many cysts develop at the points of embryonic bony fusion
• Because of the presence of teeth, cyst may develop from tooth-forming cells or developing tooth germs or from formed non-vital tooth or impacted tooth, etc.
• The teeth are always associated with some epithelium or epithelial residues which are potentially capable of forming a cyst.

Question 15. How the border of a cyst and that of a tumor differ?
Answer. The border of a cyst is mostly smooth, well-delineated and well-corticated. On the other hand, border of a tumor is ill-defied and irregular.

Question 16. Name a cyst, which frequently causes root resorption in the adjoining teeth.
Answer.Dentigerous cyst.

Question 17. Name a cyst which grows extensively in the jaw but causes little or no bony swelling.
Answer.Odontogenic keratocyst.

Question 18.In odontogenic keratocyst, why there is little or no bony swelling in the jaw even if the cyst is very large?
Answer.Because this cyst often progresses through the medullary spaces of bone and doesn’t cause much bone swelling and thereby remains clinically unnoticed even if it has affected a large part of the jaw.

Question 19. Daughter cysts are mostly present in relation to which cyst?
Answer.Odontogenic keratocyst.

Question 20. When cyst will appear bluish in color?
Answer. A cyst may look bluish in color if it is lying close to the overlying epithelial surface.

Question 21. What is the diagnostic value of cystic flid?
Answer. It helps in the diagnosis of cyst and the following parameters are checked:

• Color of the flid
• Cytology of the cystic flid content
• Microbiology of the cyst content
• Biochemical analysis, especially protein level estimation of the flid.

Question 22. Which technique helps in the estimation of protein level in the cystic flid?
Answer.Paper electrophoresis technique.

Question 23. Which cystic flid has minimum protein content?
Answer.Odontogenic keratocyst.

Question 24. Which cystic flid has maximum protein content?
Answer.Radicular cyst.

Question 25. Which cyst has the maximum recurrence rate?
Answer.Odontogenic keratocyst.

Question 26. What is called the neoplastic potential of a cyst?
Answer. Cystic epithelium sometimes can undergo neoplastic changes and gives rise to the development of benign or malignant tumors.

Question 27. What are odontogenic cysts?
Answer. Cysts which develop from the odontogenic tissues or their remnants are called odontogenic cysts.

Question 28. Name the odontogenic tissues or their remnants from which cysts can develop.
Answer.

• Developing tooth germ
• Dental lamina
• Cell rest of Serres (cell rest means the inactive cells persisting in the body after completion of their respective function)
• Cell rest of Malassez
• Reduced enamel epithelium.

Question 29. What are the common odontogenic cysts?
Answer. Odontogenic cysts are broadly divided into two; these are developmental and inflmmatory.

Question 30. Name the odontogenic cysts of developmental origin.
Answer.

• Gingival cyst of infants
• Odontogenic keratocyst (primordial cyst)
• Dentigerous (follicular) cyst
• Eruption cyst
• Lateral periodontal cyst
• Gingival cyst of adults
• Botryoid odontogenic cyst (botryoid means shaped like a bunch of grapes)
• Glandular odontogenic (sialo-odontogenic) cyst
• Calcifying epithelial odontogenic cyst.

Question 31. Name the odontogenic cysts of inflmmatory origin.
Answer.

• Radicular cyst or periapical cyst
• Residual cyst
• Paradental cyst and mandibular infected buccal cyst (paradental means having some association with tooth)
• Inflammatory collateral cyst (collateral means secondary or accessory)

Question 32. What are the non-odontogenic cysts?
Answer. Cysts originating from the non-odontogenic tissues are called non-odontogenoc cysts.

Question 33.Name the common non-odontogenic cysts.
Answer.

• Nasopalatine duct (incisive canal) cyst
• Nasolabial (nasoalveolar) cyst
• Midpalatal raphe cyst of infants
• Median palatine, median alveolar and median mandibular cysts
• Globulomaxillary cyst.

Question 34. Name the cysts which often develop from the maxillary antrum.
Answer.

• Benign mucosal cyst of the maxillary antrum
• Postoperative maxillary cyst (surgical ciliated cyst of the maxilla).

Question 35. What are the cysts of the salivary glands?
Answer.

• Mucous extravastion cyst
• Mucous retention cyst
• Ranula.

Question 36. Name the cysts, which develop on the face and neck region.
Answer.

• Dermoid and epidermoid cysts
• Lymphoepithelial (branchial cleft) cyst
• Thyroglossal duct cyst
• Anterior median lingual cyst (intralingual cyst of foregut origin)
• Oral cysts with gastric or intestinal epithelium (oral alimentary tract cyst)
• Cystic hygroma
• Nasopharyngeal cysts
• Thymic cyst.

Question 37.Defie parasitic cyst.
Answer.A cyst formed by the larva of parasite called parasitic cyst.

Question 38.Name the types of parasitic cysts.
Answer.

• Hydatid cyst
• Cysticercus cellulose
• Trichinal cyst.

Question 39.Defie odontogenic keratocyst.
Answer. Odontogenic keratocyst is a common cystic lesion of the jaw with a distinctive clinicopathologic character and a higher tendency for recurrence after treatment.

Question 39a.What was the earlier name of odontogenic keratocyst?
Answer.A primordial cyst (as people believed that the cyst used to originate from primordium of tooth germ).

Question 40. Why odontogenic keratocysts are sometimes called benign cystic neoplasms?
Answer. Odontogenic keratocysts often have a more aggressive curse than any other cystic lesion of the jaw; and for this reason, these are sometimes known as benign cystic neoplasms.

Question 41. What is nevoid basal cell carcinoma syndrome?
Answer. It is a hereditary condition, in which multiple odontogenic keratocysts occur along with the following other features:

• Multiple nevoid basal cell carcinomas of skin
• Bifi ribs and abnormalities in vertebrae
• Ocular hypertelorism and broad nasal root
• Frontal and parietal bossing with enlarged head circumference
• CNS disturbances with calcifiation of falx cerebri and abnormal shape of sella turcica, etc.
• Epidermal cyst of the skin
• Cleft lip and cleft palate in few cases.

Question 41a.What is the other name of nevoid basal cell carcinoma syndrome?
Answer.Gorlin-Goltz syndrome.

Question 41b.In relation to which syndrome, multiple odontogenic keratocysts occur?
Answer.Gorlin-Goltz syndrome.

Question 42. From which cells or tissues do odontogenic keratocyst arises?
Answer. It is mostly believed that the keratocyst develops due to the cystic degeneration of the cells of the stellate reticulum in a developing tooth germ (before its calcifiation starts).

Question 43. Name the other cells or tissues from which odontogenic keratocysts can arise?
Answer. These cysts arise mainly from the following cells or tissues:

• Dental lamina or its remnants
• Primordium of the developing tooth germ or enamel organs (primordium is the fist recognizable stage in the embryonic development and differentiation of a particular organ or tissue)
• Sometimes from the basal layer of the oral epithelium.

Question 44. From which cells or tissues the daughter cysts arise?
Answer. The daughter cysts, a common fiding in keratocyst, probably develop from the remnants of the dental lamina.

Question 45. What is the incidence rate of odontogenic keratocyst?
Answer.About 1 percent among all types of jaw cysts.

Question 46. What is the common age of occurrence of odontogenic keratocyst?
Answer.Mostly second and third decade of life.

Question 47.In case of odontogenic keratocyst, which jaw is more often affected?
Answer.The majority of these cysts develop in relation to mandible (75%) as compared to maxilla.

Question 48. Which areas of the bone affect mandibular lesions of odontogenic keratocyst?

Answer. Among the mandibular lesions, 50% of the cases occur at the angle of the mandible which extend for varying distances into the ascending ramus and the body of the mandible.
Few cysts absolutely occur in the body of the mandible.

Question 49. Name the cyst which can cross the midline of mandible.
Answer. Few odontogenic keratocysts can cross the midline of mandible.

Question 50. Which areas of the bone affect maxillary lesions of odontogenic keratocyst?
Answer. Maxillary lesions more frequently involve the anterior part of the jaw, however some lesions can develop from the posterior region. Few lesions can even develop in relation to the maxillary air sinus.

Question 51. What is an extraosseous odontogenic keratocyst?
Answer. This is a rare condition where the cyst develops in relation to the soft tissue (mostly gingiva).

Question 52. Describe the clinical presentation of odontogenic keratocyst.
Answer.

• In the initial stages, odontogenic keratocysts are asymptomatic
• Larger lesions however produce swelling of the jaw with facial asymmetry
• Pain in the jaw along with mobility and displacement of the teeth
• Bony expansion is minimal in odontogenic keratocyst
• Paresthesia of the lower lip and teeth may be present occasionally.

Question 53. Why expansion of bone is minimal in odontogenic keratocyst?
Answer. Bony expansion is minimum because the cyst mostly spreads via the medullary spaces of bone and therefore remarkable bony swelling is usually absent, despite the cyst being very large.

Question 54. What are the radiographic features of odontogenic keratocyst?
Answer.

• Odontogenic keratocyst often radiographically present multilocular radiolucent areas in the jaw, with a typical soap-bubble appearance
• Few mandibular lesions enlarge and extend to the other side of the bone by crossing the midline
• Sometimes multiple cysts may be seen in the jaw.

Question 55. What are the radiological types of keratocyst?
Answer. There are four radiological types of odontogenic keratocysts:
Replacement type
Envelopmental type
Extraneous type
Collateral type.

Question 56. What is a replacement type of odontogenic keratocyst?
Answer. When a keratocyst develops in place of a developing normal tooth, it is called as the replacement type. In such cases, there will be absence of a normal tooth in the dental arch.

Question 57. What is an envelopmental type of odontogenic keratocyst?
Answer. Developmental type of keratocyst entirely encloses an impacted tooth within the jawbone.

Question 58. How the extraneous type of odontogenic keratocyst appears?
Answer. When a keratocyst develops away from the tooth bearing areas of the jaws, it is called extraneous type of keratocyst.

Question 59. What is a collateral type of odontogenic keratocyst?
Answer. When a keratocyst develops between the roots of a tooth, it is called collateral type of keratocyst.

Question 60.Which lesions are included in the differential diagnosis of odontogenic keratocyst?
Answer.

• Ameloblastoma
• Dentigerous cyst
• Aneurysmal bone cyst (aneurysm means—dilating or widening)
• Odontogenic myxoma
• Stafie bone cyst
• Lateral periodontal cyst.

Question 61. Describe the macroscopic fiding of odontogenic keratocyst.
Answer.

• On necked eye examination, the odontogenic keratocyst presents a cystic cavity;which is filed with a thick cheesy material (keratin debris)
• The cystic wall is thin and friable; and is diffiult to separate from the bone wall.

Question 62. Describe the cystic flid in odontogenic keratocyst.
Answer. Aspiration of the cystic content reveals either a straw colored flid or sometimes a clear flid.

Question 63. What is paper electrophoresis?
Answer. Paper electrophoresis is a technique often used for determination of soluble protein level.

Question 63a.Name the soluble proteins present in cystic flid.
Answer.Albumin, globulin and firinogen, etc.

Question 64. How the protein levels in different cystic flids vary on the basis of paper electrophoresis?
Answer. Electrophoretic treatment reveals the soluble protein levels in various cysts in following manner:

• Odontogenic keratocyst: Soluble protein levels in cystic flid is below 3–5 g/100 mL.
• Non-keratinizing cysts: Soluble protein level is higher about 5–11 g/100 mL.

Question 65.Why protein level estimation is important in cystic flid of the jaw cysts?
Answer.Because it is an important diagnostic parameter in the diagnosis of a cyst; if the soluble protein level in a cyst is less than 4.5 g/100 mL. It should be considered a keratocyst and if the level is more than 5.0 g/100 mL. It should be a non-keratinizing cyst.

Question 66. Keratin is a protein and the cystic flid of odontogenic keratocyst contains large amounts of it, but still why the protein levels in this cyst is lower than other cysts?
Answer. Paper electrophoresis measures only the soluble protein level in a cystic flid; the cystic flid of keratocyst does not show a higher score because of high keratin content as it is an insoluble protein.

Question 67. Describe the histopathology of odontogenic keratocyst.
Answer.

• A cystic cavity which is lined by a uniform looking keratinized stratifid odontogenic epithelium having 6–8 cell layers thickness
• The basal layer of the cystic epithelium is made up of tall columnar cells or cuboidal cells
• Large amount of desquamated keratin is often found within the cystic lumen
• The cystic lining often shows a folded or corrugated appearance, which could be due to unequal growth pattern of the lining at different places
• The cyst often shows the presence of many daughter cysts or satellite cysts.

Question 68. What are daughter cysts?
Answer. Daughter cysts or satellite cysts are small microcysts; which are found in large numbers within the connective tissue wall of odontogenic keratocyst.

Question 69.What is the signifiance of these daughter cysts?
Answer.

• These are of diagnostic value for keratocysts (other cysts do not have it)
• Since these are very tiny in size, some daughter cysts may be left behind during surgery in a large odontogenic keratocyst, which later on grow up and cause recurrence.

Question 70.Can the lining epithelium of odontogenic keratocyst undergo dysplastic changes?
Answer. The cystic epithelium of odontogenic kerato cyst sometimes shows dysplastic changes,and on rare occasions, the lining epithelium may undergo malignant transformation.

Question 71. Name the special investigations done in odontogenic keratocysts.
Answer.

• Computed tomographic scan (CT scan)
• Ultrasound
• Magnetic resonance imaging (MRI)
• DNA analysis of the lining cells of the cystic epithelium
• Scanning electron microscopy (SEM)
• Transmission electron microscopy (TEM)
• Immunohistochemistry.

Question 72. Describe the use of computed tomographic scan (CT scan) in odontogenic keratocyst.
Answer.

• It helps in understanding the exact size of the lesion
• It can help in assessing the exact extent of the lesion by showing the boundary
• It is an excellent technique in determining the involvement of cortical plates particularly
  in localizing the point of perforation in the cortical plate
• It helps in the assessment of soft tissue involvement
• In maxillary lesion particularly where it is extending toward the base of the skull, CT scan can effectively determine the position of the cyst.

Question 73. What is the diagnostic use of DNA analysis of the lining cells of the cystic epithelium?
Answer.

• DNA analysis in odontogenic keratocyst can help in determining the dysplastic or malignant potential of the cystic epithelial cell
• HPV virus is sometimes detected in the cystic epithelial cells (by DNA analysis) and it is suggested that the virus can be responsible for dysplastic or malignant transformation of the cystic epithelial cells.

Question 74. Describe the use of scanning electron microscopy in odontogenic keratocyst.
Answer.

• It reveals a complex series of depressions and elevation on the cell surface in case of parakeratinized epithelium in odontogenic keratocyst
• Whereas in case of orthokeratinized epithelium a uniform, flt surface covered with layer of orthokeratin is found with no evidence of surface corrugations.

Question 75. Describe the diagnostic property of transmission electron microscopy in odontogenic keratocyst.
Answer. Transmission of electron microscopy (TEM) helps in detecting the cytoplasmic interdigitations and desmosomal junctions in lining cell surface of parakeratinized epithelium in keratocyst. The analysis of orthokeratinized cystic epithelium shows an attachment between superfiial shreds of orthokeratin and component layers of underlying keratin.

Question 76. Describe the diagnostic importance of immunohistochemistry in odontogenic keratocyst.
Answer.An immunohistochemical study using monoclonal antibodies indicates that the epithelial cells in odontogenic keratocyst appear to undergo a gradual maturation as they migrate to the upper cell layers. However, in dentigerous and radicular cyst, this type of basal to surface differentiation is absent.

Question 77. How the odontogenic keratocyst enlarges after formation?
Answer. The following are the mechanisms of enlargement of odontogenic keratocyst:

• Cell proliferation
• Osmolarity of cyst flid
• Enzymatic mechanisms.

Question 78. Describe the cell proliferation theory of cyst enlargement in keratocyst.
Answer. As odontogenic keratocyst is made up of pre-formative cells of dental lamina, they have an increased tendency for mitotic divisions. Increased mitotic activity of the cystic epithelial cells may contribute to the greater expansion or enlargement of the cyst.

Question 78a.Howosmolarity of cystic flid helps in cyst enlargement in odontogenic keratocyst?
Answer.

• The average concentration of the cystic flid is usually higher than that of blood serum (due to the presence of large amounts of soluble protein and cell breakdown products within the cystic flid)
• Because of this, there is a significant osmotic difference between the serum and the cystic flid, which helps to draw more and more flid toward the cystic lumen through the process of diffusion (osmotic)
• Moreover, an increased hydrostatic pressure in the cyst again causes resorption of bone in the jaw, which results in further expansion of the cyst.

Question 79. How the expansion of cyst continues due to higher osmolarity throughout the clinical course of keratocyst?
Answer. It is to be noted that continuous shedding of the cells of the cystic lining and incorporation of their breakdown products (mainly proteins) into the cystic flid always maintains the higher osmolarity of the flid in comparison to the blood serum. This results in a continuous tendency for the cyst to enlarge itself with time.

Question 80. How enzyme activity helps in cyst enlargement in keratocyst?
Answer. It is believed by some investigators that odontogenic keratocysts can release considerable amount of collagenase enzyme which causes destruction of collagen in the bone (collagenolysis). This results in increased bone resorption and subsequent expansion of the cyst.

Question 81. What are the treatments of odontogenic keratocyst?
Answer. Surgical enucleation and marsupialization are the two main treatment modalities in this cyst.

Question 82. Why is it necessary to excise the oral epithelium overlying the keratocyst?
Answer. The oral epithelium, which is overlying the cystic lesion, has to be excised to eliminate the possibility of further recurrence (because some cysts may develop from the basal layer of the oral epithelium itself).

Question 83. What are the treatments of odontogenic keratocyst in case of repeated recurrence?
Answer. Usually, the recurrence rate is very high in odontogenic keratocyst; and in case of repeated recurrence, jaw resection is often recommended.

Question 84. What are the causes of higher recurrence in odontogenic keratocyst?
Answer.

• Satellite cyst
• New cyst formation
• Keratinization pattern
• Nature of cyst lining
• Basal layer of oral epithelium
• Too much conservative surgical approach.

Question 85. How satellite cysts cause recurrence in odontogenic keratocyst?
Answer. The satellite cyst or daughter cyst are microcystic lesions scattered throughout the cyst capsule; these cysts often remain undetected within the tissue during treatment. The higher rate of recurrence in keratocysts could be due to the enlargement of the satellite cysts after the removal of the original keratocyst.

Question 86. After treatment of a keratocyst, can there be a new keratocyst formation in the jaw, which appears like a recurrence?
Answer. New cyst formation in the jaw is common after treatment of the original keratocyst;
since the cells of the odontogenic keratocysts have an aggressive potential for multiplication (as these are all pre-formative group of cells of the dental lamina) and this tendency may often cause formation of newer cysts in the jaw, which often appears as recurrence.

Question 87. Can the type of keratinization in the cystic epithelium indicate the recurrence potential of the keratocyst?
Answer. Yes, odontogenic keratocysts with parakeratinized epithelium often have more possibility of recurrence than those cysts which have orthokeratinized epithelial lining.

Question 88. How the nature of cystic lining can inflence in recurrence of keratocyst?
Answer.Nature of cystic lining may increase the risk of recurrence in the following manners:

• If the lining epithelium is parakeratinized
• If the lining epithelium is extremely fragile and can’t be removed completely during surgery
• If the lining epithelium is corrugated, it is also diffiult to remove completely at the time of surgery.

Question 89.What is a dentigerous cyst?
Answer. A dentigerous cyst is a common odontogenic cystic lesion which encloses the crown of an impacted tooth at its neck portion. The cyst develops due to abnormal dilatation of the dental follicle.

Question 90. From which cells, dentigerous cyst develops?
Answer. A dentigerous cyst is derived from the reduced enamel epithelial cells, which surround the crown of an impacted or unerupted tooth.

Question 91. How does dentigerous cyst develop?
Answer. The cyst develops due to accumulation of flid in between the reduced enamel epithelium and the tooth crown.

Question 92. Is there any triggering factor which stimulates the process of cyst formation?
Answer. When the cyst develops around the crown of an impacted permanent tooth, periapical inflmmation in the overlying deciduous tooth may be the triggering factor. Sometimes the triggering factor may be unknown.

Question 93. At what level of the impacted tooth the dentigerous cyst attaches?
Answer. A dentigerous cyst always attaches to the cervical margin (cementoenamel junction) of the involved tooth.

Question 94. What is the position of crown of the impacted tooth in relation to the cyst?
Answer. The crown of the involved tooth is located within the lumen of the cyst while the root remains outside.

Question 95. What is the common age of occurrence of dentigerous cyst?
Answer. The cyst mostly occurs in second and third decade of life.

Question 96. What are the common sites of occurrence of dentigerous cyst?
Answer.

• Mandibular third molar area is the most common site for dentigerous cyst
• The other sites include maxillary canine, mandibular second premolar and maxillary third molar areas
• The cyst also frequently occurs in relation to supernumerary teeth or odontomes
• Although rare, dentigerous cyst can develop in relation to an unerupted deciduous tooth.

Question 97. How an asymptomatic dentigerous cyst is often detected?
Answer. In many cases, smaller cysts remain asymptomatic and are detected incidentally during the routine radiographic examinations for a over-retained deciduous tooth or a missing permanent tooth.

Question 98. Describe the clinical appearance of dentigerous cyst.
Answer. A dentigerous cyst generally presents a slow enlarging, bony hard swelling of the jaw with expansion of the cortical plates of bone. Larger lesions can cause massive facial swelling with derangement of occlusion and facial asymmetry, etc.

Question 99. When can flctuations develop in a dentigerous cyst?
Answer. In untreated cases of dentigerous cysts, severe expansion of bone results in thinning of the cortical plates; on palpation, the affected area of bone gives a crepitus-like sensation.
Moreover, if the overlying bone is completely lost due to a growing cyst, flctuations may be felt in the area.

Question 100. What happens when the cyst is secondarily infected?
Answer. Infected dentigerous cyst shows accelerated swelling, pain and sinus formation with occasional pus discharge on the mucosa overlying the cyst.

Question 101.When can paresthesia and anesthesia develop in dentigerous cyst?
Answer. Paresthesia and anesthesia on the affected part of the jaw often develop if the cyst causes compression of the regional nerve.

Question 102. Can pathological fracture occur in bone affected by dentigerous cyst?
Answer. Yes, in few untreated lesions, pathological fractures of the jawbone may occur due to extreme bony weakness.

Question 103. What is the general radiographic appearance of a dentigerous cyst?
Answer. Radiographically dentigerous cyst reveals a well-defied, round, unilocular radiolucent area in the jaw enclosing the crown of an impacted tooth.

Question 104. How the margin of the dentigerous cyst appears radiographically?
Answer. The periphery of the cyst is often bordered by well-corticated or sclerotic margin.

Question 105. Can dentigerous cyst cause root resorption in the neighboring teeth?
Answer. Dentigerous cysts in most of the cases cause resorption of the roots of the neighboring erupted teeth.

Question 106. Why root resorption is more common in dentigerous cyst?
Answer.

• Reduced enamel epithelial cell, from which dentigerous cysts are derived are capable of causing root resorption in deciduous teeth. The same property is retained by the cells of the dentigerous cyst, and hence, they are capable of causing root resorption in permanent teeth
• The cystic epithelial cells release some chemical substances which can cause resorption of roots.

Question 107. What are the radiological types of dentigerous cyst?
Answer. There are three types:

• Central type
• Lateral type
• Circumferential type.

Question 108.Among all three radiographic types, which one is the most common?
Answer. The central type is the most common among all radiographic types.

Question 109. Describe the central type of dentigerous cyst.
Answer. When the cyst encloses the crown of an impacted tooth symmetrically from all sides, then the crown appear to be placed at the center of the cystic cavity. This radiographic variant is called central type of dentigerous cyst.

Question 110. Describe the lateral type of dentigerous cyst.
Answer. In this case, the cystic cavity is located on one side of the involved crown. It results from deflction of the dental follicle on one side of the crown during the eruption of the tooth.

Question 111. In which situation, lateral type of dentigerous cyst develops?
Answer. This type is mostly seen when the cyst develops in relation to a partially erupted, mesioangular type of mandibular third molar.

Question 112. How the circumferential type looks like?
Answer. Circumferential type radiographically appears to enclose the entire tooth.

Question 113. Does the dentigerous cyst in circumferential type really encloses the entire tooth?
Answer.No, the cyst as usual encloses only the crown; however, when we see the impacted tooth in a two-dimensional image in the background of a very large cyst, it often gives the typical circumferential type of appearance.

Question 114. How the cystic flid in dentigerous cyst appears?
Answer. The cyst is usually filed with a straw colored flid.

Question 115. What is the soluble protein content in the cystic flid of dentigerous cyst?
Answer. It contains about 5-gram percent of soluble protein.

Question 116. Name the lesions which fiure in the differential diagnosis of dentigerous cyst.
Answer.

• Adenomatoid odontogenic tumor (AOT)
• Compound odontome
• Unicystic ameloblastoma
• Odontogenic keratocyst
• Calcifying epithelial odontogenic cyst.

Question 117. Describe the histological appearance of dentigerous cyst.
Answer. Histologically dentigerous cyst reveals the presence of a cystic cavity, which is lined by a thin layer of non-keratinized, odontogenic epithelium (about 2 to 3 cell layer thickness).
The lining epithelium is supported by a loosely arranged connective tissue stroma that often resembles the odontogenic ectomesenchyme.

Question 118. Name one important biologic characteristic of dentigerous cyst.
Answer. The cystic epithelium may undergo neoplastic transformations.

Question 119. What is mural proliferation?
Answer. Localized bud-like growth from the wall of the cyst due to proliferation of lining epithelial cells, may be seen in few areas of dentigerous cyst; this phenomenon is known as mural proliferation.

Question 120. What mural proliferation in a cyst indicates?
Answer. It indicates neoplastic transformations in the lining epithelial cells of the cyst.

Question 121. Neoplastic transformation in dentigerous cyst commonly leads to the development of which tumor?
Answer. It often leads to the development of ameloblastoma.

Question 122.Besides ameloblastoma, which other tumors can develop from the dentigerous cyst lining?
Answer. Besides ameloblastoma, many other tumors e.g. squamous cell carcinoma and intraosseous mucoepidermoid carcinoma, etc. can develop from the dentigerous cyst lining.

Question 123. Name the factors which help in the expansion of dentigerous cyst in the jaw.
Answer.Osmolarity and chemical mediators, e.g. interleukin-1, prostaglandins (PGE2, PGE3

Question 124. What is the treatment of dentigerous cyst?
Answer. Treatment of dentigerous cyst can be done by two methods—

• Marsupialization, this technique helps in preserving the involved tooth
• Surgical enucleation.

Question 125.Defie radicular cyst.
Answer. Radicular or periapial cyst is the most common odontogenic cystic lesion of inflmmatory origin which occurs in relation to the apex of a non-vital tooth.

Question 125a. Name the cell of origin of radicular cyst.
Answer. Cell rests of Malassez.

Question 126. Name one common clinical test done for detection of radicular cyst.
Answer.Vitality test of the involved tooth (as the tooth is always non-vital in radicular cyst).

Question 127. What is a residual cyst?
Answer. In case of a radicular cyst, if the involved tooth is exfoliated or extracted and the cyst remains within the jawbone, the condition is known as residual cyst.

Question 128. What are the phases of development of radicular cyst?
Answer. There are four phases:

• Phase of initiation
• Phase of proliferation
• Phase of cystifiation
• Phase of enlargement.

Question 129. What happens during the phase of initiation in the development of radicular cyst?
Answer. During this phase, the bacterial infection of the dental pulp or direct inflammatory effect of necrotic pulpal tissue in a non-vital tooth causes stimulation of the cell rest of Malassez which are present within the bone near the root apex of teeth.

Question 130. Describe the phase of proliferation in the development of radicular cyst.
Answer. In the phase of proliferation, excessive and exuberant proliferation of cell rests of Malassez occurs, which leads to the formation of a large mass of immature proliferating epithelial cells at the periapical region of the affected tooth.

Question 131. Describe the phase of cystifiation during the development of radicular cyst.
Answer.

• This phase starts once a large bulk of the cell rests of Malassez is formed at the periapical region of the involved tooth
• The peripheral layers of cells of the bulk get adequate nutritional supply but the centrally located cells are often deprived of proper nutritional supply
• As a result the central or innermost group of cells undergo ischemic liquefactive necrosis while the peripheral group of cells survive
• This eventually gives rise to the formation of a cavity that contains a hollow space or lumen inside the mass of the proliferating cell rests of Malassez.

Question 132. Describe how a small radicular cyst enlarges gradually into a large cyst.
Answer. Following are the mechanisms of cyst enlargement:

• Higher osmotic tension of the cystic flid: It causes progressive increase in the amount of flid inside its lumen with an increased internal hydrostatic tension within the cyst. The process results in cyst expansion due to resorption of the surrounding bone
• Chemical mediators: The epithelial cells of the cystic lining often release some bone-resorbing factors like prostaglandins and collagenase, etc. which destroy the bone and thereby facilitate the expansion of cyst.

Question 133. Many people have non-vital teeth in the jaw for years; why only few of them develop radicular cyst?
Answer.

• Immunological factor: Some kind of immune mechanisms may prevent cyst formation in few people while defective immunity may cause development of the same cyst in others
• Genetic factor: Sometimes the process of cyst formation is genetically determined.

Question 134. What is the commonest type of odontogenic cyst?
Answer.Radicular cyst.

Question 135. What is the incidence rate of radicular cyst?
Answer. It constitutes about 50 percent or more among all types of jaw cysts.

Question 136.Radicular cyst occurs more commonly in maxilla or mandible?
Answer.Maxilla.

Question 136a.Why radicular cysts develop more often in relation to maxilla?
Answer.

• Occurrences of more caries in the upper anterior teeth
• Presence of dense in dente in the upper lateral incisors (which leads to frequent pulp exposures in tooth with subsequent development of radicular cyst)
• Upper teeth are more prone to injury and become non-vital as compared to lower teeth.

Question 137. What are the common signs and symptoms of a non-vital tooth?
Answer.

• If the tooth is often grossly carious or has a history of trauma
• If the tooth may be fractured or broken by injury
• If the tooth is discolored
• If the tooth does not respond to thermal or electric pulp testing.

Question 138. What are the clinical features of radicular cyst?
Answer.

• Always there is a non-vital tooth associated with the cyst
• The smaller cystic lesions are usually asymptomatic and are detected only when a radiograph is taken
• The larger lesions often produce a slow enlarging, painless, bony hard swelling of the jaw with expansion and distortion of the cortical plates.

Question 139. What is the clinical appearance of a residual cyst?
Answer.Swelling in the portion of the jaw from where a tooth has been extracted in the recent past.

Question 140. What is the usual fate of a residual cyst?
Answer. It regresses slowly and spontaneously.

Question 141. What happens when a radicular cyst is secondarily infected?
Answer. An infected radicular cyst presents the following features:

• Pain and erythema in the area of the jaw
• Extrusion and tenderness in the associated tooth
• Discharge of pus
• Formation of sinus tract in the periapical area of the involved tooth.

Question 142. What is a lateral radicular cyst?
Answer. When a radicular cyst develops at the opening of a large accessory pulp canal on the lateral aspect of the tooth root, it is called a lateral radicular cyst.

Question 143. What is the common radiographic picture of a radicular cyst?
Answer. Cyst presents a well-defied, unilocular, round shaped radiolucent area at the root apex of a non-vital tooth. It can be of variable size and the margin of the cyst is well-corticated.

Question 144. How the lateral radicular cysts appear radiographically?
Answer. The lateral radicular cyst appears as a semi-circular radiolucency on the lateral aspect of the root with loss of lamina dura of alveolar bone.

Question 145. What is the radiographic appearance of residual cyst?
Answer. Residual cyst appears as a round or oval radiolucent area in the alveolar ridge; wherefrom a tooth was extracted previously.

Question 146. Describe the macroscopic appearance of radicular cyst.
Answer.

• Radicular cyst appears as a round or ovoid soft tissue sack with a thick capsule,which is attached to the root apex of a non-vital tooth
• Within the lumen, a thin straw-colored flid or a thick, paste-like, yellow-brown coagulum is found
• Cholesterol crystals within the cyst may appear as glistening particles.

Question 147. What is the usual level of soluble protein in the cystic flid of radicular cyst?
Answer. Paper electrophoresis indicates the presence of about 5 gram percent of soluble protein in it.

Question 148. What is the basic histological appearance of radicular cyst?
Answer. Histologically radicular cyst shows the presence of a cystic cavity, lined by a nonkeratinized, stratified squamous epithelium of about 6 to 20 cell layers thickness and the
cyst often has a thick, well-vascularized capsule.

Question 149. What is arcading pattern and in which cyst it can be seen?
Answer. The proliferating cystic epithelium may sometimes grow in a peculiar fashion by enclosing or encircling a mass of connective tissue capsule from all sides. This pattern of growth is called arcading pattern. It is seen in radicular cyst.

Question 150.Which type of inflmmatory cells are predominantly found in radicular cyst?
Answer. The cyst capsule of radicular cyst is often infitrated by chronic inflmmatory cells, predominantly the plasma cells.

Question 151. What are cholesterol clefts and in which cyst these are found?
Answer. These are multiple small, ribbon-shaped or needle-shaped, cleft-like spaces are seen either in the cystic lumen or in the connective tissue capsule of radicular cyst.

Question 152. What are Russell’s bodies?
Answer. Russell’s bodies are sometimes seen in the radicular cyst, the structure represents a plasma cell being surrounded by immunoglobulins.

Question 153. Name the lesions which fiure in the differential diagnosis of radicular cyst.
Answer.

• Periapical granuloma
• Central giant cell granuloma
• Periapical abscess
• Cementoma (stage I)
• Traumatic bone cyst
• Bony artefact.

Question 154. What is the treatment of radicular cyst?
Answer. Small cysts are treated by root canal treatments of the affected teeth and apical curettage. The larger cysts are treated either by enucleation or marsupialization.

Question 155. What is an eruption cyst?
Answer.Eruption cyst is an odontogenic cyst which surrounds the crown of a tooth that has erupted through the bone, but not the soft tissue.

Question 156. How does the eruption cyst develop?
Answer. The eruption cyst develops due to the accumulation of flid within the follicular space of an erupting tooth, which has come out of bone but still lying within the soft tissue of the jaw.

Question 157. From which cells, eruption cysts are derived?
Answer. It is often called the soft tissue variant of dentigerous cyst.

Question 158. Eruption cysts are derived from which cells?
Answer. The cysts are derived from reduced enamel epithelial cells.

Question 159.Generally at what age eruption cysts develop?
Answer.During childhood.

Question 160.In relation to which teeth, eruption cysts develop?
Answer. It can develop in relation to both deciduous as well as permanent teeth.

Question 161. Describe the clinical appearance of eruption cyst.
Answer. Clinically the cyst presents a small, rounded, soft and flctuant swelling on the alveolar ridge, immediately superior to an erupting tooth.

Question 162. What is an eruption hematoma?
Answer. When masticatory trauma causes hemorrhage within an eruption cyst, the condition is called eruption hematoma and the lesion often appears bluish-purple or red in color.

Question 163. How does the eruption cyst histologically appear?
Answer. Histologically eruption cyst is similar to the dentigerous cyst and exhibits a thin lining of non-keratinized squamous epithelium. However, some cysts have numerous epithelial ghost cells within the lumen.

Question 164. What is the treatment of eruption cyst?
Answer.No treatment is generally required as the cyst disappears spontaneously once the tooth erupts in to the oral cavity. Sometimes in long standing lesions, the roof of the cyst is excised to allow the tooth to erupt in the oral cavity.

Question 165. What is a lateral periodontal cyst?
Answer. The lateral periodontal cyst is an uncommon developmental odontogenic cyst that develops in immediate association with the lateral root surface of an erupted vital tooth.

Question 166. What is the other name of this cyst?
Answer. It is also called as intrabony counterpart of gingival cyst of adults.

Question 167. What are the possible cells of origin of lateral periodontal cyst?
Answer. It arises from any of these odontogenic cell remnants present within the periodontal ligament tissue:

• Reduced enamel epithelial cells
• Cell restd of Malassez
• Cell rests of Serre.

Question 168. What is the common age of occurrence of lateral periodontal cyst?
Answer. It commonly occurs in adult males.

Question 169.In relation to which teeth, lateral periodontal cyst commonly occurs?
Answer.Maxillary and mandibular anterior teeth.

Question 170. Describe the clinical features of lateral periodontal cyst.
Answer. The cyst is generally asymptomatic; but in few cases, there may be a small, painless soft tissue swelling within or just anterior to the interdental papillae of a vital tooth.

Question 171. What is the average size of lateral periodontal cyst?
Answer.Usually less than 1 centimeter in diameter.

Question 172. What is the radiographic appearance of lateral periodontal cyst?
Answer. Radiographically the cyst presents a small, unilocular, teardrop-shaped radiolucent area surrounded by a thin, delicately corticated margin on the lateral aspect of the root (near the crest of the alveolar ridge).

Question 173. Name the lesions fiuring in the differential diagnosis of lateral periodontal cyst.
Answer.

• Lateral periodontal abscess or granuloma
• Radicular cyst
• Early ameloblastoma
• Collateral type of primordial cyst
• Lateral dentigerous cyst
• Globulomaxillary cyst.

Question 174. What is the histological appearance of lateral periodontal cyst?
Answer. Histologically the cyst presents a small cystic cavity lined by non-keratinized stratified squamous epithelium of 2 to 3 cell layers thickness. The cystic epithelial cells are flt and are backed by a thin non-inflamed connective tissue wall.

Question 175. What are the Gingival cysts of the newborn?
Answer. Gingival cysts of the newborn are multiple small, nodular, keratin-filed, cystic lesions seen in the oral cavity of new-borns or very young infants.

Question 176. At what age gingival cysts develop?
Answer.From birth up to the age of 3 months.

Question 177. What are the types of gingival cysts of the newborn?
Answer. Depending upon their locations in the oral cavity, these cysts are divided into several types:

Question 178. What are cysts of the dental lamina?
Answer. These lesions are mostly found along the alveolar ridge and are odontogenic in origin (arising from the remnants of dental lamina).

Question 179. What are the Epstein’s pearls?
Answer. These small creamy colored cystic lesions are found linearly along the mid-palatine raphe and are probably derived from the epithelium, entrapped along the line of fusion of the palate during embryogenesis.

Question 180. What are Bohn’s nodules?
Answer. Bohn’s nodules are small cysts, which are usually found along the junction of the hard and soft palate and on the buccal and lingual aspects of alveolar ridge. These types of cysts are derived from remnants of the mucous glands.

Question 181.Gingival cysts of newborn affect which jaw more often?
Answer. The gingival cysts of newborn involve the maxillary arch more often than mandibular arch.

Question 182. Describe the clinical features of gingival cysts of the new-born.
Answer. Clinically these cysts often appear as multiple, asymptomatic, small discrete, white nodules; which measure about 2 to 3 millimeters in diameter.

Question 183. What is the histological feature of gingival cysts of the new-born?
Answer. The cysts exhibit small keratin-filed cystic cavities, which are lined by thin and flttened squamous epithelium.

Question 184. What is the treatment of gingival cysts of the newborn?
Answer.No treatment is required as these cysts undergo spontaneous regression with time.

Question 185. What are gingival cyst of adults?
Answer. Gingival cysts of the adults are small developmental odontogenic cysts of the gingival soft tissue.

Question 186. From which cells does gingival cysts of adults?
Answer. These are mostly derived from the cell rests of the dental lamina (cell rest of Serre).

Question 187. At what age gingival cysts of adults develop usually?
Answer.Fifth and sixth decade of life (after 40 years of age).

Question 188. What is the gender prevalence of gingival cysts of adults?
Answer. These are more prevalent among females.

Question 189. Which jaw is more frequently affected in gingival cysts of adults?
Answer. It is more common in relation to mandible in comparison to maxilla.

Question 190. Which area of the gingiva is more frequently affected in gingival cysts of adults?
Answer. The cyst particularly occurs on the facial side of gingiva in the canine-premolar region.

Question 191. How gingival cysts of adults clinically appear?
Answer. This extraosseous cyst clinically presents a fim but compressible, flid-filed, dome-like painless swelling on the gingiva around the canine-premolar area.

Question 192. How the gingival cysts of adult and lateral periodontal cysts are interrelated?
Answer. It is often believed that gingival cysts of adult and lateral periodontal cysts represent the extraosseous and intraosseous manifestations of the same entity.

Question 193. What can be the possible radiographic features of gingival cysts of adult?
Answer. Since gingival cysts of adult are entirely extraosseous lesions they do not produce any radiographic change in the bone. However in some cases there may be a pressure induced faint round superficial depression (cupping out) in the underlying alveolar bone.

Question 194. Describe the histological features of gingival cysts of adult.
Answer. Histologically the cyst presents a cystic cavity lined by a thin epithelial lining of flt or cuboidal cells having 2 to 3 cell layer thickness. Many of the lining epithelial cells exhibit pyknotic nuclei with perinuclear cytoplasmic vacuoles. Layers of keratin may be present in the cystic lumen.

Question 195. What is a Sialo-odontogenic cyst?
Answer. These are large intraosseous odontogenic cysts, which often exhibit an aggressive course.

Question 196. Why sialo-odontogenic cyst is also known as glandular odontogenic cyst?
Answer. Although it is an odontogenic cyst, the lining epithelial cells are capable of glandular differentiation; as a result, the cyst consists of both stratifid squamous epithelium as well as numerous mucus-secreting cells; the later cells give a glandular character to the cyst and they often produce pools of mucin within the cyst cavity.

Question 197. What is the cell of origin of sialo-odontogenic cyst?
Answer. The cyst arises from the remnants of dental lamina.

Question 198. What are the clinical appearances of sialo-odontogenic cyst?
Answer. Sialo-odontogenic cysts are extremely rare lesions which often develop in the anterior part of mandible. Some cysts are slow enlarging and asymptomatic while others are aggressive lesions, which may attain a very large size and may even cross the mandibular midline.

Question 199. Describe the histological appearances of sialo-odontogenic cyst?
Answer. The cyst is lined by a thin squamous epithelial lining with presence of several small glandular structures or micro-cysts within the lining epithelium. Organization of the glandular elements may result in the formation of acinar-like clusters which may produce large amount of mucin in the cystic lumen.

Question 200. What is the treatment and prognosis of sialo-odontogenic cyst?
Answer. Surgical excision is the treatment of choice and the cyst has a strong tendency to recur.

Question 201.What are botryoid odontogenic cysts?
Answer.Botryoid odontogenic cysts are rare odontogenic cystic lesions which resemble cluster of grapes.

Question 202.How botryoid odontogenic cyst is related to lateral periodontal cyst?
Answer. It is a variant of lateral periodontal cyst.

Question 203.What is the histological appearance of botryoid odontogenic cyst?
Answer.

• Histologically botryoid odontogenic cyst reveals multiple cystic cavities separated from one another by fie firous septa
• The cystic cavities are lined by non-keratinized cuboidal or squamous epithelium,which are of 1–2 cell layer thickness
• Focal areas of glycogen containing clear cell clusters are often found along the lining.
• Sometimes bud-like proliferations of the lining epithelial cells protrude into the cystic lumen.

Question 204. Define calcifying epithelial odontogenic cyst.
Answer. Calcifying epithelial odontogenic cyst is a relatively uncommon odontogenic cystic lesion of the jawbones.

Question 205. Name one important character of this cyst.
Answer.Because of its biological nature on many instances, this cyst is considered as a tumor.

Question 206. What is the other name of calcifying epithelial odontogenic cyst?
Answer.Gorlin’s cyst.

Question 207.From which cells does calcifying epithelial odontogenic cyst develop?
Answer.The cyst probably develops from the reduced enamel epithelial cells or remnants of odontogenic epithelium in the dental follicle, gingiva or bone.

Question 208.What is the common age of occurrence of calcifying epithelial odontogenic cyst?
Answer.Mostly the cyst develops in the second decade of life.

Question 209.What are the common sites of calcifying epithelial odontogenic cyst?
Answer.Both jaws are affected but the most favored site is the mandibular premolar region; other common sites include anterior parts of maxilla and mandible. Occasionally extraosseous lesions develop from the gingiva.

Question 210.Describe the clinical features of calcifying epithelial odontogenic cyst of bone.
Answer.Intraosseous cyst presents a bony hard, painless, swelling of the jaw with expansion and distortion of cortical plates and displacement of regional teeth, etc. Large bony lesions can cause perforation of the cortex and some cysts can develop in association with an odontome.

Question 211.How the extraosseous lesions of calcifying epithelial odontogenic cyst clinically appear?
Answer.Extraosseous lesions produce circumscribed, sessile or pedunculated gingival swelling; the associated teeth are vital.

Question 212.Describe the radiographic appearance of calcifying epithelial odontogenic cyst.
Answer.Radiographically the cyst presents unilocular or multilocular radiolucent area with a wellcorticated margin.Within the lesion, multiple small, irregular radiopaque calcifid foci of varying radiodensity are often found.

Question 213.Describe the histological appearance of calcifying epithelial odontogenic cyst?
Answer.

• The cyst exhibits a lining epithelium made up of odontogenic keratinized epithelial cells, with about 6 to 8 cell layer thickness
• The basal cells of the lining epithelium are columnar or sometimes cuboidal in nature, and they often exhibit a palisading arrangement (these cells resemble ameloblasts) (palisading refers to a monolayer of relatively long cells arranged loosely perpendicular to a surface and parallel to each other)
• The luminal surface epithelium often shows the presence of many ghost cells and areas of calcifiation
• The connective tissue capsule contains many satellite microcysts and multiple multinucleated giant cells.

Question 214.What are ghost cells?
Answer.In the lining epithelium of calcifying epithelial odontogenic cyst, often there is presence of many pale, swollen, abnormally keratinized cells with faint outline and absence of nuclei. For their typical appearance, these cells are often called ghost cells.

Question 215.How calcifiations occur in calcifying epithelial odontogenic cyst?
Answer.The ghost cells which are present in the cyst often undergo calcifiation and for this reason, there may be presence of multiple, small, basophilic calcifid bodies within the lumen of the cyst.

Question 216.Name the lesions which fiure in the differential diagnosis of calcifying epithelial odontogenic cyst.
Answer.

• Calcifying epithelial odontogenic tumor
• Adenomatoid odontogenic tumor
• Dentigerous cyst
• Ameloblastoma.

Question 217. What is a paradental cyst?
Answer.Paradental cyst is an inflmmatory odontogenic cyst which occurs in association with the root surface of an impacted or partially erupted vital tooth, usually the mandibular third molar.

Question 218.Paradental cyst arises from which cells?
Answer. The cyst arises from the cell rests of Malassez or the reduced enamel epithelium.

Question 219.What is the triggering factor that initiates the cyst?
Answer.Localized recurrent inflmmation in the associated tooth.

Question 220.Defie globulomaxillary cyst.
Answer. Globulomaxillary cyst is a common type of developmental or fisural cyst that actually
arises in the bone suture between the maxilla and premaxilla.

Question 221.What is the site of globulomaxillary cyst?
Answer.Clinically the usual location of the cyst is between maxillary lateral incisor and canine teeth.

Question 222.Describe the pathogenesis of globulomaxillary cyst.
Answer. Regarding the pathogenesis of globulomaxillary cyst, there are two theories—

• Old theory: Earlier it was believed that the globulomaxillary cyst develops as a result of proliferation of the epithelium, entrapped along the line of fusion between the maxilla and premaxilla. But recently, this concept has been questioned by many investigators as they doubt the existence of entrapped epithelium at the bony sutures.
• New theory: The globulomaxillary cyst is now being considered as a variant of primordial cyst or lateral periodontal cyst.

Question 223. What are the clinical features of globulomaxillary cyst?
Answer.This cystis usuallyasymptomaticand is detected during routine radiological examinations.
However, occasionally, it produces a small swelling in between the upper lateral incisor and canine teeth with elevation of the lip.

Question 224. When can globulomaxillary cyst become painful?
Answer. The cyst causes pain and discomfort only when it is secondarily infected.

Question 225. The teeth associated with globulomaxillary cyst are vital or non-vital?
Answer.The associated teeth are always vital.

Question 226.What is the radiographic appearance of globulomaxillary cyst?
Answer.Radiograph reveals an inverted pear-shaped, radiolucent area between the roots of the upper lateral incisor and canine.

Question 227.Describe the histological appearance of globulomaxillary cyst.
Answer. Histologically globulomaxillary cyst exhibits a cystic cavity, lined either by stratifid or pseudostratifid ciliated columnar epithelium or by thin squamous epithelium. The supporting connective tissue capsule often presents chronic inflmmatory cell infitration.

Question 228.What is the treatment of globulomaxillary cyst?
Answer.Surgical excision with preservation of involved teeth.

Question 229.Defie nasolabial cyst.
Answer.Nasolabial cyst is a rare non-odontogenic cystic lesion, which arises in the upper lip,deep into the nasolabial fold.

Question 230.What is the other name of nasolabial cyst?
Answer.Klestadt cyst.

Question 231. What is the typical location of nasolabial cyst?
Answer.Anterior maxillary vestibule, below the ala of the nose and deep in the nasolabial fold.

Question 232. What is the special characteristic of nasolabial cyst?
Answer.It is entirely a soft tissue cyst.

Question 233. What is the origin of nasolabial cyst?
Answer.The possible origin of this lesion is the lower part of the embryonic nasolacrimal duct.

Question 234.How the nasolabial cyst clinically appear?
Answer.The cyst produces a small, painless swelling in the upper lip lateral to the midline. It often obliterates the nasolabial fold, raises the ala of the nose and distorts the nostril on one side.

Question 235.Can the nasolabial cyst project into the nasal cavity?
Answer.Sometimes the cyst may project into the nasal flor and deviates the nasal vestibule.

Question 236.What is the radiographic appearance of nasolabial cyst?
Answer.Since it is entirely a soft tissue cyst, it does not exhibit any radiographic change. However,in few cases, it may produce focal pressure-induced resorption of the underlying bone.

Question 237.What is the exact term used to describe focal pressure-induced resorption of bone?
Answer.Saucerization of bone.

Question 238.What is the histological appearance of nasolabial cyst?
Answer. The nasolabial cyst presents a small cystic lumen lined by pseudostratifid ciliated columnar epithelium and supported by a connective tissue wall.

Question 239. What is the treatment of nasolabial cyst?
Answer. Surgical excision however, care should be taken so that no ugly scar is created on the lip.

Question 240. Define nasopalatine duct cyst.
Answer.Nasopalatine duct cyst is a relatively common, non-odontogenic intraosseous, cystic lesion, arising within the nasopalatine duct.

Question 241.What is the other name of this cyst?
Answer.Incisive canal cyst.

Question 242.What is the special characteristic of nasopalatine duct cyst?
Answer. It is considered to be a true developmental cyst without any controversy.

Question 243.How does the nasopalatine duct cyst develop?
Answer. It develops due to spontaneous cystic degeneration of the epithelial remnants within the embryonic nasopalatine duct.

Question 244.Name the triggering factors which help in the initiation of nasopalatine duct cyst.
Answer. The initiating factors for the development of this cyst may be any of the following:

• Trauma
• Inflmmation
• Mucus retention in the nearby minor salivary glands
• Bacterial infection.

Question 245. Can nasopalatine duct cyst develop in relation to the soft tissue?
Answer.On rare cases, the cyst may develop in the soft tissue near the opening of the incisive canal on the palate.

Question 246. What are the clinical manifestations of nasopalatine duct cyst?
Answer. The cyst clinically presents a small, painful, flctuant swelling in the midline of the anterior part of hard palate near the opening of the incisive foramen. It often causes pressure sensation on the flor of the nose and displacement of the roots of upper central incisors.

Question 247. How the nasopalatine duct cyst appears in the radiograph?
Answer. The most obvious presenting feature is a small round or heart-shaped radiolucent area between and apical to the roots of the upper central incisors in the midline.

Question 248. Why nasopalatine duct cyst is radiographically heart-shaped?
Answer. The typical heart shape of the cyst is due to the radiographic superimposition of the nasal spine; the cyst often has a well-corticated border.

Question 249.With which structure is nasopalatine duct cyst often radiographically confused?
Answer.The cyst is often confused with the incisive foramen.

Question 250. How nasopalatine duct cyst can be distinguished from incisive foramen?
Answer.

• A second radiograph should be taken at a different angle, which usually separates the incisive foramen and the nasopalatine duct cyst
• Moreover the average size of nasopalatine duct cyst is 1 to 2.5 centimeter in diameter; whereas the average size of incisive foramen is 6 millimeter in diameter only. Therefore when there is a suspected lesion measuring about 6 millimetere or less and there is no clinical symptom, the diagnosis should be incisive foramen and not a cyst.

Question 251. How the associated teeth behave in nasopalatine duct cyst?
Answer. The associated teeth (upper central incisors) are always vital.

Question 252.Describe the histological features of nasopalatine duct cyst.
Answer.Histology reveals a cystic cavity, lined by ciliated columnar or non-keratinized stratifid squamous epithelium and is backed by a connective tissue capsule.

Question 253.Describe the histological appearance of the capsule in nasopalatine duct cyst.
Answer.The capsule is made up of densely collagenous firous connective tissue, which shows the presence of neurovascular bundles (nasopalatine as well as long sphenopalatine nerves and vessels). There may also be presence of cartilaginous tissue, few mucous glands and chronic inflmmatory cells.

Question 254.What is the treatment of nasopalatine duct cyst?
Answer.Treatment is done by surgical excision.

Question 255What is a solitary bone cyst?
Answer.Solitary bone cyst represents a pseudocyst and it is characterized by a cystic cavity
within the bone.

Question 256. Name the other similar category of cysts which look like solitary bone cyst.
Answer.Traumatic bone cysts and hemorrhagic bone cysts.

Question 257.Why solitary bone cysts are called pseudocysts or false cysts?
Answer.Because solitary bone cysts do not have any lining epithelium; and instead of a lining,these cysts are lined by a firous tissue wall.

Question 258.In relation to which bones does maximum number of solitary bone cysts develop?
Answer.The overall incidence rate of this cyst is much higher in long bones.

Question 259.Which jaw is more often affected in case of solitary bone cyst?
Answer.It arises more frequently from mandible and rarely from maxilla.

Question 260.What is the common age of occurrence of solitary bone cyst?
Answer.The cysts usually occur among young people (between 10 and 20 years) and these are uncommon after the age of 25 years.

Question 261.What is the clinical appearance of solitary bone cyst?
Answer. Most of these cysts are asymptomatic and are detected accidentally during routine radiographic examinations. Few larger cysts may occur which produce painful, bony hard swellings in the jaw with paresthesia of the lip, expansion of the cortical plates and displacement of the regional teeth.

Question 262.Describe the radiological appearance of solitary bone cyst.
Answer. Radiograph reveals a unilocular or rarely multilocular radiolucent area in the bone with expansion and distortion of cortical plates. A prominent feature of the cyst is its tendency for scalloping in between the roots of the teeth.

Question 263.What occlusal view radiograph reveals in solitary bone cyst?
Answer.Occlusal view radiograph shows that the cyst always extends along the cancellous bone of the jaw.

Question 264.Name the factors which trigger the bony changes leading to the development of solitary bone cyst.
Answer.

• Local disturbance in bone growth
• Ischemic bone marrow defect
• Localized disturbed bone metabolism
• Disturbance of venous drainage in bone.

Question 265.Describe the traumatic pathway of solitary bone cyst development.
Answer. Intra-bony hemorrhage following trauma generally undergoes organization and repair.
However, if the clot forming after intrabony hemorrhage does not organize properly or in case liquefaction occurs to the clot, then healing of the bony wound does not take place at all. As a result an intrabony cavity develops which is lined by a firous tissue wall; later on, it is called the solitary bone cyst.

Question 266.Enumerate the lesions fiuring in the differential diagnosis of solitary bone cyst.
Answer.

• Aneurysmal bone cyst
• Central giant cell granuloma
• Ameloblastoma
• Calcifying epithelial odontogenic cyst
• Ameloblastic firoma
• Central ossifying firoma.

Question 267. Describe the macroscopic appearance of solitary bone cyst.
Answer.Once the cystic cavity is opened, an empty space is found in the bone which is lined by a thin firous tissue wall. The cyst often contains very little blood, blood pigments and serous flid, etc.

Question 268.Describe the histologic appearance of solitary bone cyst.
Answer. Histology reveals a cystic cavity surrounded by a loose vascular connective tissue wall with no epithelial lining. The connective tissue stroma is made up of firous tissue,showing areas of hemorrhage, hemosiderine pigmentation and bone resorption, etc.

Question 269.How the surrounding bony wall looks like once the solitary bone cyst is removed?
Answer. The bony wall surrounding the cyst appears rough.

Question 270.What is the treatment of solitary bone cyst?
Answer.The treatment is done by surgical exploration of the cyst, it helps in causing further hemorrhage in the area with subsequent healing.

Question 271. Is treatment always necessary in solitary bone cyst?
Answer.No, some cysts may resolve spontaneously.

Question 272. Define aneurysmal bone cyst.
Answer. Aneurysmal bone cyst is an uncommon cystic lesion which involves the bone anywhere in the body including the jaws.

Question 273.Name one important characteristic of aneurysmal bone cyst.
Answer. Its clinical features can be similar to that of central giant cell granuloma.

Question 274. What is the common age of occurrence of aneurysmal bone cyst?
Answer.Usually second decade of life (10 to 19 years of age group).

Question 275. What is the gender prevalence of aneurysmal bone cyst?
Answer. Females are more commonly affected.

Question 276. What are the common sites of aneurysmal bone cyst?
Answer.Mandibular molar-ramus area is most frequently affected site; maxillary lesions usually involve the posterior region.

Question 277.Describe the clinical features of aneurysmal bone cyst.
Answer.Aneurysmal bone cyst clinically presents a rapidly enlarging, diffuse, fim, painful swelling of the jaw with facial asymmetry. The swelling may be pulsatile in some cases;and in severe cases, it may cause severe expansion and thinning thereby resulting in egg-shell crackling.

Question 278.What are the clinical complications of aneurysmal bone cyst?
Answer.

• Pathological fracture of the affected jawbone
• Accidental injury or perforation to the aneurysmal bone cyst may result in profuse bleeding
• Paresthesia may develop on the affected side
• Expansion of cortical bone and derangement of occlusion
• Diffiulty in mouth opening if the cyst causes impingement on the capsule of the temporomandibular joint
• Maxillary lesions sometime invade into the paranasal sinuses and cause nasal bleeding, pressure sensation in the eye and nasal obstructions.

Question 279. Describe the radiographic features of aneurysmal bone cyst.
Answer. Radiograph reveals a multilocular radiolucent area in the bone, with a typical honeycomb appearance.

Question 280. What are the most unique radiographic fidings in an aneurysmal bone cyst?
Answer.

• Ballooning expansion of the cortical plates of bone
• Resorption of roots of the adjoining teeth.
• Blow–out bulging of the lower border of mandible.

Question 281. Describe the pathogenesis of aneurysmal bone cyst.
Answer. There are two possible pathways of development of this cyst:

• One theory states that the cyst arises as a result of trauma with subsequent venous occlusion inside the bone
• The other theory states that the lesion develops as a result of cystic transformation in a pre-existing pathology, especially the central giant cell granuloma.

Question 282.Which lesions are taken into consideration for differential diagnosis of aneurysmal
bone cyst?
Answer.

• Fibrous dysplasia
• Intraosseous hemangioma
• Traumatic bone cyst
• Giant cell tumor of bone
• Osteoblastoma.

Question 283.Is aneurysmal bone a true cyst or a pseudo cyst?
Answer.Aneurysmal bone cyst is a pseudocyst as it has no lining epithelium.

Question 284. Describe the macroscopic appearance of aneurysmal bone cyst.
Answer. Macroscopically the lesion exhibits a cystic cavity surrounded by a thin bony wall and it is filed with a vascular soft tissue that often appears as a blood-soaked sponge.

Question 285.What is usually found after aspiration of aneurysmal bone cyst?
Answer. Aspiration often reveals fresh blood.

Question 286.What are the histopathological fidings in aneurysmal bone cyst?
Answer.Microscopically aneurysmal bone cyst presents multiple blood filed spaces, lined by many spindle-shaped cells or flt endothelial cells. Epithelial lining is absent in this cyst and there is often presence of multiple multinucleated giant cells, scattered osteoids, areas of hemorrhage and hemosiderine pigmentations, etc.

Question 287.What is the treatment of aneurysmal bone cyst?
Answer.Surgical excision.

Question 288. What is a mucocele?
Answer.Cystic lesion developing from the salivary glands is commonly known as mucocele.

Question 289.Mucoceles predominantly develop from the major or the minor salivary glands?
Answer.These lesions develop mostly in relation to the minor salivary glands and rarely in
relation to the major salivary glands.

Question 290. What are the types of mucoceles?
Answer. Mucoceles basically are of two types:

• Mucous retention cyst
• Mucous extravasation cyst.

Question 291.How the mucous retention cysts develop?
Answer. The mucous retention cyst develops as a result of obstruction to the duct of the affected salivary gland with subsequent accumulation of saliva either within the gland or within
its duct.

Question 292. Name the factors which help in the formation of mucous retention cyst.
Answer.

• Calculus formation within the gland or it’s duct
• Scarring at the duct orifie
• Obstruction of salivary flw due to mucin plugging
• Crushing of the duct (as a result of trauma) with loss of patency
• Atresia (congenital absence of duct in the salivary gland).

Question 293.How mucous extravasation cyst forms?
Answer.A mucous extravasation cyst develops due to rupture of the salivary gland duct, which
leads to spillage or extravasations of saliva into the surrounding connective tissue. Once
a large amount of saliva is collected within the tissue, it is called an extravasation cyst.

Question 294. What is the most important cause of development of mucous extravasation cyst?
Answer. Local trauma is believed to be the most important cause.

Question 295.Why mucous retention cyst is called a true cyst?
Answer.Mucous retention cyst is a true cyst since it has a cystic epithelial lining made up of
glandular epithelial cells of the salivary glands.

Question 296. Mucous extravasation cyst is a true or a pseudocyst?
Answer.Mucous extravasation cyst is a pseudo or a false cyst, as it has no epithelial lining.

Question 297.What is the common age of occurrence of mucous extravasation cyst?
Answer.Mucous extravasation cyst is more commonly seen in children.

Question 298. What is the common age of occurrence of mucous retention cyst?
Answer. Mucous retention cyst develops more often among adults.

Question 299. What is the commonest intraoral site for development of mucocele?
Answer. Mucoceles of intraoral minor glands predominantly affect the lower lip.

Question 300.In case of mucoceles developing in the major salivary glands, which gland is
mostly affected?
Answer.Parotid.

Question 301. Name one interesting feature of mucocele.
Answer. Mucoceles produce swelling, which develop only during mealtime and are absent during
the in between periods.

Question 302. Describe the clinical features of superficial lesion of mucocele developing in the minor salivary glands.
Answer. The superficial lesions appear as small, raised, vesicle-like, flctuant areas; measuring from few millimeters to few centimeters in diameter. These lesions often have a bluish appearance.

Question 303. What are the clinical features of a deep-seated lesion of mucocele developing in the minor salivary glands?
Answer. Deep-seated lesions produce diffuse, relatively fim, painless swellings in the oral cavity.

Question 304.How do you differentiate between mucous retention and mucous extravasation cysts?
Answer.

Question 305. Describe the histology of mucous retention cyst in minor gland.
Answer. Mucous retention cyst histologically presents a small cystic cavity which is filed with mucous and is lined by flttened cuboidal or columnar epithelial cells of the salivary gland duct. Sometimes the cystic epithelium may have papillary foldings, which often project into the cystic lumen and the mucocele almost always has a minor salivary gland in its vicinity.

Question 306. What is the histological appearance of a mucous extravasation cyst?
Answer. This lesion microscopically presents a cystic cavity in the connective tissue which is filed with mucus, but there is no lining epithelium present in this cyst. Instead of a lining epithelium, the cystic cavity is often surrounded by a compressed connective tissue wall or a granulation tissue.

Question 307.Name the lesions, which fiure in the differential diagnosis of mucoceles.
Answer.

• Salivary gland tumor
• Intraoral vesicle or bulla
• Lipoma
• Fibroepithelial polyp
• Cysticercosis.

Question 308. What is the treatment of mucocele?
Answer. Mucoceles are treated by surgical excision of the lesion along with the involved gland.

Question 309. What is a ranula?
Answer. Ranula is a form of mucocele that typically produces a large, bluish, flctuant swelling in the flor of the mouth.

Question 310. Is ranula a mucous retention or a mucous extravasation cyst?
Answer. The ranula represents a mucous extravasation cyst of the salivary gland.

Question 311.Name the glands from which ranulas generally develop?
Answer. Ranulas occur due to spillage of saliva from the sublingual salivary glands or rarely the submandibular gland or sometimes from the minor salivary glands.

Question 312. What are the causes of formation of ranula?
Answer.

• Obstruction to the duct by calculus (sialolith) formation
• Compression of the duct by trauma or a growing tumor in the vicinity
• Perforation of the duct due to injury
• Absence of the duct itself (atresia)
• Scar or stricture formation to the duct, especially after surgery.

Question 313. Describe the clinical appearance of a ranula.
Answer. Clinically ranula presents a dome-shaped, soft, flctuant, unilateral swelling in the flor of the mouth. The lesion is generally very large (several centimeters in diameter) which often fils up the flor of the mouth and causes deviation of the tongue.

Question 314. What is the typical color of a ranula?
Answer. The ranulas typically have a bluish translucent appearance.

Question 315. What does ranula often look similar to?
Answer. Clinically the lesion often looks like the “distended under belly of a large frog.’

Question 316. How the term ranula has evolved?
Answer. The name has come from the Latin word rana which means frog.

Question 317. What is a plunging type of ranula?
Answer.When the ranula herniates through the mylohyoid muscle and produces a swelling in the
neck, it is called a plunging type of ranula.

Question 318.Name one serious complication caused by ranula.
Answer. On rare occasions, it can cause air-way obstructions.

Question 319. What is the treatment of ranula?
Answer. Treatment is done by surgical excision or marsupialization; few lesions rupture spontaneously.

Question 320.What is a dermoid cyst?
Answer. It is a developmental cyst derived from the remnants of embryonic skin.

Question 321.In which age group dermoid cyst generally develops?
Answer.Children and young adults.

Question 322. What are the common sites of dermoid cyst in the head and neck area?
Answer.Skin around the eyes, anterior upper neck and flor of the mouth on the midline.

Question 323. How dermoid cyst of flor of mouth differs from a ranula locationwise?
Answer. Dermoid cyst always develops in the midline of flor of the mouth, and thus, it differs from ranula which develops on the lateral aspect of the midline.

Question 324. What is the clinical appearance of dermoid cyst?
Answer. It produces a painless swelling in the midline of the flor of mouth which often has a doughy or rubbery consistency.

Question 325. Describe the appearance of a dermoid cyst located above the geniohyoid muscle.
Answer.

The cyst, which develops above the geniohyoid muscle, presents a sublingual swelling in the midline of flor of the mouth. It often causes elevation of the tongue with diffiulty in eating, talking or sometimes even breathing.

Question 326. Describe the appearance of a dermoid cyst located below the geniohyoid muscle.
Answer. The cyst located below the geniohyoid muscle often produces a midline swelling in the submental region which often produces a ‘double chin’ appearance.

Question 327. What is the histologic appearance of dermoid cyst?
Answer.

• A cystic cavity lined by orthokeratinized stratifid squamous epithelium which exhibits hair follicles, sebaceous glands and erector pili muscles, etc.
• The cavity lumen is often filed with sebum, desquamated keratin and hair shafts.
• The cyst capsule is composed of a narrow zone of compressed connective tissue.

Question 328. What is a surgical ciliated cyst of maxilla?
Answer. It is an iatrogenic cyst which develops as result of surgery, involving the maxillary sinus.

Question 329. How a surgical ciliated cyst of maxilla appears clinically?
Answer. The cyst generally occurs in middle aged or older adults and often causes pain and tenderness in the maxilla. All the patients have a previous history of surgery in the maxillary bone.

Question 330. What is the radiographic appearance of surgical ciliated cyst of maxilla?
Answer. Radiography shows a well-circumscribed radiolucency in close proximity of the maxillary sinus.

Question 331. How the surgical ciliated cyst of maxilla appears histologically?
Answer. Histology reveals a cystic cavity lined by a pseudostratified ciliated columnar epithelium and is surrounded by a normal or inflmmed connective tissue stroma.