Odontogenic Neoplasms Oral Pathology Question And Answers

Odontogenic Neoplasms Question And Answers

Question 1. What are odontogenic neoplasms?
Answer. Odontogenic neoplasms are a complex group of lesions derived from the dental formative tissues or their remnants (tissues associated with the development of tooth and its supporting structures).

Question 2. Why these neoplasms are called so?
Answer. Because the constituent tissues in each of these neoplasms can resemble various tissues found during any phase of normal odontogenesis (from inception of the tooth germ to tooth eruption).

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

Question 3. When tooth formation begins in humans?
Answer. The tooth formation or odontogenesis begins in the 6th week of intra-uterine life.

Question 4. Name the common odontogenic cells or tissues from which neoplasms can develop.
Answer.

• Cells of dental lamina
• Remnants of dental lamina or cell rests of Serre
• Ameloblast cells
• Reduced enamel epithelial cells
• Odontoblast cells
• Cells from epithelial root sheath of Hertwig
• Cell rests of malassez
• Odontogenic ectomesenchymal cells
• Cementoblast cells.

Question 5. Give the modifid WHO classifiation of odontogenic neoplasms.
Answer.

• A. Benign

1. Odontogenic epithelium without odontogenic ectomesenchyme
   • Ameloblastoma
   • Squamous odontogenic tumor
   • Calcifying epithelial odontogenic tumor (pindborg tumor)
   • Adenomatoid odontogenic tumor.
   • Odontogenic Neoplasms 159
2. Odontogenic epithelium with odontogenic ectomesenchyme with or without hard tissue formation
   • Ameloblastic firoma
   • Ameloblastic firodentinoma
   • Ameloblastic firoodontoma
   • Odontoameloblastoma
   • Calcifying odontogenic cyst
   • Complex odontoma
   • Compound odontoma.
3. Odontogenic ectomesenchyme without included odontogenic epithelium
   • Odontogenic firoma
   • Myxoma
   • Cementoblastoma (benign cementoblastoma, true cementoma)

• B. Malignant
  • Odontogenic carcinomas
    • Malignant ameloblastoma
    • Primary intraosseous carcinoma
    • Clear cell odontogenic carcinoma
• Odontogenic sarcomas
  • Ameloblastic firosarcoma
  • Ameloblastic firoodontosarcoma
  • Ameloblastic firodentinosarcoma
  • Neoplasms of debatable origin
  • Melanotic neuroectodermal tumor of infancy
  • Congenital gingival granular cell tumor (congenital epulis).

Question 6. Define ameloblastoma.
Answer. Ameloblastoma is a benign locally aggressive neoplasm arising from the odontogenic epithelium and it is the most common odontogenic neoplasm of the oral cavity.

Question 7. How the term ameloblastoma has evolved?
Answer. The term ameloblastoma has evolved from the early English words Amel meaning enamel, and blastos meaning germ.

Question 8. When the neoplasm ameloblastoma was fist recognized and what was its earlier name?
Answer. It was first recognized by Cusack in 1827; it was named adamantinoma in 1885 by Luis-Charles Malassez. It was fially renamed as ameloblastoma in 1934 by Ivey and Churchill.

Question 9. Name the factors, which may predispose to the formation of ameloblastoma.
Answer.

• Trauma in the jawbone
• Chronic infection in bone
• Previous chronic inflmmation
• Previous extraction of tooth
• Dietary factors
• Slow viral infection.

Question 10. From which odontogenic cells do ameloblastomas arise?
Answer. Ameloblastoma develops from the odontogenic epithelial cells or their remnants but the exact cell of its origin is not very clearly known. According to different investigators, the possible cells or tissues may be the following:

• Enamel organ of the developing tooth germ
• Cell rest of Serre (remnants of dental lamina)
• Epithelial lining of the odontogenic cysts, especially the dentigerous cyst
• The basal cell layer of the oral epithelium (rarely)
• Reduced enamel epithelium
• Cell rest of Malassez.

Question 11. Mention the common age of occurrence of ameloblastoma.
Answer. It is more common in second, third, fourth, and fith decade of life.

Question 12. What is the mean age of occurrence of ameloblastoma?
Answer. The mean age of occurrence is about 32 years.

Question 13. What is the gender prevalence of ameloblastoma?
Answer. Males are affected more often than females.

Question 14. Which jawbone is more often involved by ameloblastomas?
Answer. Mandible is far more commonly affected than maxilla (ratio is 80:20).

Question 15. Describe the common sites of ameloblastoma in both jaws.
Answer.

• Mandibular lesions: Ameloblastomas of mandible mostly occur in the molar-ramus area (70% cases); although some lesions may develop in the premolar (20%) or symphysis (10%) regions
• Maxillary lesions: Maxillary tumors also generally involve its posterior part
• Extraosseous lesions: These are rare lesions and occur mostly in relation to the gingiva.

Question 16. Name one important characteristic of maxillary ameloblastoma.
Answer. Lesions of the posterior maxilla often have a tendency to invade into the antrum or the nasal flor.

Question 17. Name the different types of ameloblastomas of the jaw.
Answer.

• Unicystic ameloblastoma
• Multicystic ameloblastoma
• Peripheral ameloblastoma
• Malignant ameloblastoma.

Question 18. In case of ameloblastoma, what type of history is often given by the patient about the disease?
Answer. Most of the patients report with a typical long time history of presence of an “abscess” or a cyst in the jaw; which was operated on several occasions but has recurred after each surgery.

Question 19. Describe the clinical features of ameloblastoma.
Answer. Clinically ameloblastoma presents the following features:

• A slow enlarging, painless, ovoid or fusiform, bony hard swelling of the jaw
• Large lesions cause gross facial asymmetry due to severe expansion and distortion of the cortical plates of the jawbone
• Displacement and mobility of teeth in the affected part of the jaw; with occasional pain and paresthesia
• Larger lesions of ameloblastoma may cause so severe expansion and thinning of the bone that ‘flctuations” or “egg-shell crackling” may develop in the jaw
• Severely weakened bone in ameloblastoma may exhibit “pathological fractures”
• The mucosa overlying the tumor appears normal and the regional teeth are always vital.

Question 20. What is pathological fracture?
Answer. When fracture occurs in a healthy bone it is called conventional fracture but when fracture occurs in a bone that was weakened by any disease process it is called pathological fracture.

Question 21. What is the basic difference between pathological fracture and conventional fracture?
Answer. In case of pathological fracture, a diseased bone may break even under normal functional forces e.g. normal eating and chewing, etc whereas in case of conventional fracture a strong forceful blow or trauma to the bone is required.

Question 22. Name the common jaw lesions, which can lead to pathological fracture.
Answer.

• Ameloblastoma
• Osteogenesis imperfecta
• Hyperparathyroidism
• Osteopetrosis
• Osteoporosis
• Malignant tumors e.g. osteosarcoma
• Metastatic tumors
• Rickets
• Osteoradionecrosis
• Fibrous dysplasia of bone
• Osteomyelitis
• Large untreated cysts.

Question 23. What is egg-shell crackling?
Answer. In few bony lesions, particularly long-standing ameloblastoma; the affected jawbone becomes severely expanded and extremely thin (just like the thin outer-shell of an egg).
Such thin shell of bone crumbles or cracks under digital pressure and the phenomenon is called egg-shell crackling.

Question 24. Name the complications often caused by long-standing, untreated ameloblastoma.
Answer.

• Enormous swelling with gross facial deformity
• Eggshell crackling of bone
• Pathological fractures
• Some lesions may undergo malignant transformations
• Perforation of cortical plates of jaw with protrusion of tumor mass as a soft nodule.
• Invasion of tumor into maxillary antrum or orbit or nasopharynx
• Metastasis of the tumor cells into the distant parts of the body.

Question 25. Describe the features of extra osseous (soft tissue) ameloblastoma.
Answer. Extra osseous ameloblastoma of the jaw often produces a small, painless, nodular growth in the gingiva.

Question 26. What is desmoplastic ameloblastoma?
Answer. Desmoplastic ameloblastoma is a special variant, which unlike other lesions of ameloblastoma develops from the anterior part of the jaw, especially the maxilla. This tumor has the characteristic of producing excessive firosis in the vascular stroma of a neoplasm.

Question 27. Describe the typical radiographic appearance of ameloblastoma.
Answer.

• Radiographically ameloblastoma presents a well-defied, multilocular, radiolucent area in the jaw with a typical honey-comb or soap-bubble appearance
• Few lesions can be unilocular too
• Border of the lesion is irregular with a characteristic scalloped margin
• Larger lesions may cause root resorption of adjoining teeth, expansion of the lower border of mandible and perforation of cortical plates of bone.

Question 28. In multilocular ameloblastoma, radiographically when should it be called soapbubble type and when honey-comb type?
Answer. When the loculations or cavities are large, the appearance will be soap-bubble type and when the loculations are small the appearance will be called honey-comb type.

Question 29. Does ossification or calcifiation occur inside the lesion of ameloblastoma?
Answer. No, ossifiation or calcifiation never occurs in ameloblastoma as tumor cells never produce any calcifiation.

Question 30. In which type of ameloblastoma a mixed radiolucent and radiopaque appearance is found and why?
Answer. Desmoplastic ameloblastoma presents a mixed radiolucent and radiopaque appearance; it happens due to osseous metaplasia within the connective tissue of the tumor (although tumor cells in ameloblastoma do not produce any calcifiation).

Question 31. Can ameloblastoma develop from a pre-existing cyst?
Answer. Yes, the tumor can develop from the cystic lining of a dentigerous cyst.

Question 32. Which lesions must be included in the differential diagnosis of ameloblastoma?
Answer.

• Odontogenic keratocyst (primordial cyst)
• Dentigerous cyst
• Central giant cell granuloma
• Central hemangioma
• Aneurysmal bone cyst
• Odontogenic Neoplasms 163
• Pindborg’s tumor
• Neurilemmoma.

Question 33. Describe the macroscopic appearance of ameloblastoma.
Answer. Macroscopically the cut section of ameloblastoma exhibits a grayish-white or grayishyellow mass, containing few cyst-like spaces with no evidence of calcifiation.

Question 34. Describe the histopathological appearance of ameloblastoma.
Answer. Histologically ameloblastoma shows neoplastic proliferation of odontogenic epithelial cells (ameloblast like cells) in different histologic patterns, e.g. plexiform and follicular, etc.

Question 35. What is reverse polarization phenomenon in ameloblastoma?
Answer. In ameloblastoma the neoplastic cells characteristically exhibit their nuclei moved away from the basement membrane and this particular phenomenon is called reverse polarization.

Question 36. Name the different histological types of ameloblastoma.
Answer.

• Plexiform type
• Follicular type
• Acanthomatous type
• Basal cell type
• Granular cell type
• Desmoplastic type.

Question 37. Describe in brief the plexiform type of ameloblastoma (plexiform means-resembling or forming a web-like plexus).
Answer.

• There will be proliferation of neoplastic odontogenic epithelial cells in the form of long continuous anastomosing strands or cords within a loose, vascular connective tissue stroma
• The peripheral layer of cells in the epithelial cords are tall columnar in nature often resembling ameloblasts
• The triangular-shaped cells at the center portion of the cords often resemble the stellate reticulum cells; while those located between columnar cells and stellate reticulum cells often resemble the stratum intermedium.

Question 38. Describe the histological appearance of follicular ameloblastoma.
Answer.

• The follicular ameloblastoma exhibits neoplastic proliferation of odontogenic epithelial cells in the form of multiple, discrete follicles or islands within the firous connective tissue stroma
• Each follicle is bordered on the periphery by a single layer of tall columnar cells resembling ameloblasts
• These cells have well-defied nuclei, which are situated away from the basement membrane on the opposite pole of the cytoplasm (reverse polarization)
• Cells located at the centre of each follicle resemble stellate reticulum cells while those located in between the peripheral and the central group of cells, appear as the stratum intermedium
• Microcyst formation is often seen both within and outside the follicles.

Question 39. What is acanthomatous type of ameloblastoma?
Answer. It is a type of follicular ameloblastoma in which, the stellate reticulum-like cells at the center of the follicles undergo squamous metaplasia.

Question 40. What is granular cell type of ameloblastoma?
Answer. This type structurally resembles the follicular ameloblastoma; the cytoplasm of the stellate reticulum-like cells and even the ameloblast-like cells appear swollen and these cells are often densely packed with multiple, coarse, eosinophilic granules.

Question 41. Which other lesion does granular pattern of ameloblastoma resembles histologicaly?
Answer. Granular cell myoblastoma.

Question 42. Describe the basal cell type of ameloblastoma.
Answer. In this type of ameloblastoma many follicular structures exhibit excessive proliferation of uniform looking basaloid cells with the absence of stellate reticulum or other centrally located cells.

Question 43. Which other lesion does basal cell pattern of ameloblastoma resembles histologically?
Answer. These tumors often resemble basal cell carcinomas.

Question 44. What is desmoplastic type of ameloblastoma?
Answer. In this type of ameloblastoma, the epithelial islands or strands are small and are widely separated by dense firous tissue. The cells are mostly cuboidal in shape and are darkly stained with little or no tall columnar ameloblast-like cells seen.

Question 45. Name one important characteristic of desmoplastic pattern of ameloblastoma.
Answer. In this form of ameloblastoma, the neoplastic cells often infitrate into the surrounding trabecular bone.

Question 46. What is unicystic ameloblastoma?
Answer. Unicystic ameloblastoma is a separate entity from conventional ameloblastoma; which arises either as a de-novo lesion or it develops due to neoplastic transformation of a pre-existing cystic epithelium.

Question 47. Why it is called unicystic ameloblastoma?
Answer. Because unlike the multilocular conventional ameloblastoma, this tumor exhibits a wellcircumscribed, unilocular radiolucent area in the bone.

Question 48. What are the histological types of unicystic ameloblastoma?
Answer. There are three histological types:

• Luminal unicystic ameloblastoma
• Intra-luminal unicystic ameloblastoma
• Mural unicystic ameloblastoma (mural means occurring on the wall of a cavity).

Question 49. Describe the luminal unicystic ameloblastoma.
Answer. This type of unicystic ameloblastoma occurs on the luminal surface of a cyst and the base of the tumor is made up of cystic epithelium, backed by a connective tissue wall.
The lesion consists of a basal layer of columnar or cuboidal cells, which exhibit reverse
polarity of the nuclei.

Question 50. What is an intraluminal unicystic ameloblastoma?
Answer. This tumor produces several nodular growths; which project from the cyst lining into the cystic lumen. The lesion sometimes fils up the entire lumen and few lesions resemble plexiform ameloblastomas.

Question 51. What is mural unicystic ameloblastoma?
Answer. In this lesion the neoplastic cells instead of projecting inside the cystic lumen infitrates into the connective tissue wall of the cyst capsule.

Question 52. What is the treatment of ameloblastoma?
Answer. Surgical enucleation of the tumor with thorough curettage of the surrounding bone.

Question 53. Which type of ameloblastoma exhibits more recurrence?
Answer. Follicular variants appear to recur more than plexiform variants.

Question 54. Among the unicystic and conventional (non-unicystic) ameloblastomas, which type shows more recurrence?
Answer. The unicystic tumors recur less frequently than non-unicystic conventional tumors.

Question 55. What is the rational treatment in case of repeated recurrence of ameloblastoma?
Answer. Radical surgical approach may have to be adopted in cases of repeated recurrences.

Question 56.Defie adenomatoid odontogenic tumor (AOT).
Answer. The adenomatoid odontogenic tumor is a relatively uncommon, well-circumscribed,odontogenic neoplasm characterized by the formation of multiple ducts-like structures by the tumor cells.

Question 57. Why the tumor is named adenomatoid?
Answer. Because histologically the tumor cells produce numerous duct-like structures, which give a glandular or so-called adenomatoid appearance to the lesion.

Question 58. From which cell adenomatoid odontogenic tumor originates?
Answer. The tumor probably arises from the reduced enamel epithelium; although some investigators also believe that it develops from either the dental lamina or from a preexisting dentigerous cyst.

Question 59. What is the common age of occurrence of adenomatoid odontogenic tumor?
Answer. It is more common in young age. Most commonly occurs in second and third decade of life.

Question 60. In which gender adenomatoid odontogenic tumor is more prevalent?
Answer. Distinctly more prevalent among females.

Question 61. What is the common site of occurrence of adenomatoid odontogenic tumor?
Answer. The tumor most typically occurs in the maxillary anterior region (upper lateral incisorcanine area).

Question 62. How does adenomatoid odontogenic tumor appears clinically?
Answer. The tumor often presents a slow enlarging, small, bony hard swelling in the maxillary anterior region; with elevation of the upper lip, displacement teeth and mild pain, etc.
Many lesions are associated with an uperupted tooth (mostly the upper canine).

Question 63. Describe the radiographic appearance of adenomatoid odontogenic tumor.
Answer. Radiographically adenomatoid odontogenic tumor presents a well-defied, unilocular, radiolucent area at the anterior maxilla; which often encloses a tooth or tooth-like structure (mostly maxillary canine). Multiple small, radiopaque foci may be present inside the lesion; which often produces the so called snow-flke calcifiations.

Question 63a. Which lesions are often included in the differential diagnosis of adenomatoid odontogenic tumor?
Answer.

• Dentigerous cyst
• Globulomaxillary cyst
• Lateral periodontal cyst
• Odontome
• Unicystic ameloblastoma.

Question 64. Describe the histopathological appearance of adenomatoid odontogenic tumor.
Answer. The tumor exhibits proliferation of multiple spindle shaped, neoplastic cells in several duct-like patterns; each duct-like structure is bordered by a single layer of tall columnar cells, resembling ameloblasts or preameloblasts. The central space of each duct is filed with an eosinophilic coagulum and these ductal structures give a glandular appearance to the tumor. Small foci of calcifiations are often seen scattered throughout the lesion.

Question 65.How adenomatoid odontogenic tumors are treated?
Answer. These tumors are treated by surgical enucleation.

Question 66. Define calcifying epithelial odontogenic tumor (CEOT).
Answer. The calcifying epithelial odontogenic tumor is a locally aggressive odontogenic neoplasm, which is also known as Pindborg’s tumor (named after Prof JJ Pindborg who fist reported it).

Question 67. Calcifying epithelial odontogenic tumor arises from which cells?
Answer. The lesion may arise from any of the following tissues:

• Cells of the stratum intermedium of the enamel organ
• Reduced enamel epithelium
• Remnant cells of the dental lamina.

Question 68. How calcifying epithelial odontogenic tumor differs from ameloblastoma?
Answer.

• The tumor cells in CEOT are spherical or polyhedral in shape unlike the tall columnar cells as seen in ameloblastoma.
• CEOT always contain some calcifid materials within the tumor, which is never seen in amelosblastoma.

Question 69. Describe the clinical features of calcifying epithelial odontogenic tumor.
Answer. The tumor usually presents a slow enlarging, painless, bony hard swelling of the jaw with expansion and distortion of the cortical plates and displacement of regional teeth.

Question 70. Describe the radiographic features of calcifying epithelial odontogenic tumor.
Answer. The tumor presents a well-defied, multilocular radiolucent area; which contains multiple,small, radiopaque calcified foci of varying radiodensity. The calcifiation within the tumor often produces a typical driven-snow appearance.

Question 71. How calcifying epithelial odontogenic tumor appears histologically?
Answer. Histologically the tumor reveals sheets or islands of closely packed, polyhedral epithelial cells, in a non-inflmed connective tissue stroma. The neoplastic cells have hyperchromatic nuclei and prominent intercellular bridges. Several calcifid substances and amyloids are characteristically present in the lesion.

Question 72. What is the treatment of calcifying epithelial odontogenic tumor?
Answer. Surgical enucleation is the treatment of choice.

Question 73. Define squamous odontogenic tumor.
Answer. Squamous odontogenic tumors are rare, sometimes multifocal, potentially aggressive neoplasms derived from the odontogenic epithelium.

Question 74. Squamous odontogenic tumor originates from which cells?
Answer. It probably originates from either the remnants of dental lamina or from the cell rests of Malassez.

Question 75. Describe the clinical features of squamous odontogenic tumor.
Answer. The tumor often presents a painless swelling on the gingival areas of the jaw with mobility and looseness of the regional teeth. Intraosseous lesions are usually small and slow enlarging.

Question 76. What is the radiographic appearance of squamous odontogenic tumor?
Answer. Radiographically the tumor presents a well-circumscribed, semilunar or triangular shaped, unilocular radiolucent area with sclerotic border. The lesion is often found between contagious teeth near their roots.

Question 77. How squamous odontogenic tumor appears histologically?
Answer. Microscopically squamous odontogenic tumor presents round or oval shaped islands of well-differentiated squamous epithelium in a mature firous connective tissue stroma.
Individual cell keratinization is often seen in this tumor often with formation of focal areas of keratin or parakeratin.

Question 78.Defie ameloblastic firoma.
Answer. Ameloblastic firoma is a true benign odontogenic tumor, in which both the epithelial and the mesenchymal elements are neoplastic (in ameloblastoma only the epithelial tissue is neoplastic and in odontogenic firoma only the mesenchymal tissue is neoplastic).

Question 79. At what age ameloblastic firoma usually develops?
Answer. Usually below the age of 20 years (average age 14 years).

Question 80. What is the common site for ameloblastic firoma?
Answer. Mandibular posterior (premolar-molar) region is the most common site.

Question 81. Describe the clinical features of ameloblastic firoma.
Answer. The tumor presents a slow-growing, painless, bony hard swelling of the jaw with mobility of the regional teeth. This tumor develops predominantly above the impacted or unerupted molar teeth as a peri-coronal lesion.

Question 82. What is the radiographic appearance of ameloblastic firoma?
Answer. The tumor usually presents a well-defied, unilocular or multilocular radiolucent area that often resembles ameloblastoma or dentigerous cyst.

Question 83. Describe the histological appearance of ameloblastic firoma.
Answer. Both the epithelial as well as the mesenchymal elements are neoplastic in this tumor:

• Epithelial components: The epithelial components of the tumor consist of multiple sharply defied, strands, islands or narrow cords; which often proliferate in a mushroom-like fashion.
• Mesenchymal components: The mesenchymal component of the tumor consists of plump stellate or ovoid cells with a loose firoblastic storma that often resembles the dental papilla of the developing tooth.

Question 84.What is ameloblastic firo-odontome?
Answer. It is a benign neoplasm of odontogenic origin and is characterized by the presence of combined features of ameloblastic firoma along with the presence of calcifid enamel or dentin like tissues.

Question 85. What is the clinical appearance of ameloblastic firo-odontome?
Answer. This is a tumor of the younger people, which mostly affects the posterior part of jaw. It develops mostly in association with an impacted or missing tooth and often produces progressive, painless swelling of the jaw with expansion of the cortical plates.

Question 86. What is the radiographic appearance of ameloblastic firo-odontome?
Answer. Radiograph shows unilocular radiolucent area (rarely multilocular) containing multiple radiopaque foci having radiodensity similar to that of tooth.

Question 87.How ameloblastic firo-odontome appears histologically?
Answer. Histologically the tumor exhibits neoplastic odontogenic epithelial cells proliferating in the form of small discrete islands or narrow cords as may be seen in ameloblastic firomas.
However, the loose and primitive-looking connective tissue stroma (resembling dental papilla) of the tumor also shows multiple calcifid foci of enamel and dentin matrix in close proximity to the epithelial components.

Question 88.Defie odontomes.
Answer. Odontomes are a group of common hamartomatous odontogenic lesions with limited growth potential. These lesions are capable of producing normal-appearing enamel,dentin, cementum and pulp, etc. in an unorganized fashion.

Question 89. During which stage of tooth development odontomes are formed?
Answer. The tumor probably occurs during the development of teeth at a point after the stage of histodifferentiation but prior to the stage of morphodifferentiation.

Question 90. What types of neoplasm are odontomes?
Answer. They come under the following category: Neoplasm containing odontogenic epithelium with odontogecic ectomesenchyme; with or without hard tissue formations.

Question 91. Name the different types of odontomes.
Answer. Two types of odontomes are found:

• Compound odontome
• Complex odontome.

Question 92. According to the site of development, how compound odontome differs from the complex odontome?
Answer.

• Compound odontomes: Involves the anterior part of the jaw (inter-canine area)
• Complex odontomes: Involves the posterior (premolar-molar) region of the jaw.

Question 93. Describe the clinical features of odontomes.
Answer.

• Clinically small odontomes produce painless, asymptomatic lesions in the jaw
• Larger lesions can be as big as 6 cm in diameter and they cause expansion and distortion of cortical plates, displacement of teeth and malocclusion, etc.
• Odontomes are often associated either with an impacted tooth or a retained deciduous tooth.

Question 94. Describe the radiographic appearances of odontomes.
Answer.

• Compound odontome: The compound odontomes radiographically appear as numerous, small, miniature teeth or tooth-like structures; projecting from a single focus and thus apparently look like a bag of teeth.
• Complex odontome: They radiographically appear as round or oval or sunburst-like,conglomerated radiopaque mass within the jawbone.

Question 95. Describe the histological features of odontomas.
Answer.

• Compound odontoma: The fully developed compound odontoma histologically presents an encapsulated mass of multiple separate denticles; embedded in a firous tissue stroma
• Complex odontome: Histologically it presents as an irregularly arranged mass of well formed enamel, dentin, cementum and pulp, etc.

Question 96.Defie odontogenic firoma.
Answer. Odontogenic firoma is a rare benign neoplasm derived from connective tissue of odontogenic origin.

Question 97. What are the types of odontogenic firoma?
Answer. Odontogenic myxomas are generally of two types:

• Peripheral (extraosseous) odontogenic firoma
• Central (intraosseous) odontogenic firoma.

Question 98. Describe the clinical features of peripheral odontogenic firoma.
Answer. Peripheral odontogenic firoma develops extraosseously from the tooth-bearing areas of the jaw as slow enlarging, painless, exophytic, well-circumscribed, sessile growth of the gingiva.

Question 99. Describe the radiological features of peripheral odontogenic firoma.
Answer. Since peripheral odontogenic firoma is a soft tissue lesion, generally it does not produce any radiographic change. However, few lesions may cause following:

• Saucerization of the cortical bone or widening of the periodontal ligament space
• Numerous foci of small radiopaque masses are sometimes found within few lesions (saucerization means surgical excavation of tissue by forming a shallow depression).

Question 100. Describe the histological features of peripheral odontogenic firoma.
Answer.

• Histologically peripheral odontogenic firoma reveals a mass of dense connective tissue with few spindle-shaped firoblasts, which is separated from the adjacent normal loose connective tissue
• Surface epithelium shows long, slender rete-pegs projecting deep into the connective tissue
• Small islands of odontogenic epithelium may be present near the rete pegs. Areas of hyalinized tissue with calcifiation can be present within the lesion.

Question 101.Which lesions of oral cavity look very similar to peripheral odontogenic firoma?
Answer.

• Peripheral ossifying firoma
• Peripheral giant cell granuloma
• True firoma
• Neurofiroma
• Fibroepithelial polyp.

Question 102. How central odontogenic firoma clinically appears?
Answer. Central odontogenic firoma produces a slow enlarging, non-descript, painless swelling of the jaw with displacement of teeth or formation of gap between them.

Question 103.Describe the radiological features of central odontogenic firoma.
Answer. Radiograph exhibits a well-circumscribed, rounded, unilocular radiolucent area in the jaw with sclerotic borders. Lesions often contain several small radiopaque flcks of varying radiodensity. Resorption of roots of the adjoining teeth is often seen in this tumor.

Question 104. Describe the histological features of central odontogenic firoma.
Answer. Histologically central odontogenic firoma presents a cellular connective tissue,containing numerous thin strands of odontogenic epithelium, stellate firoblast cells being arranged in whorled pattern and areas of spherical or diffuse calcifiations.

Question 105. Name the lesions which simulate central ossifying firoma.
Answer.

• Calcifying epithelial odontogenic tumor (CEOT)
• Ameloblastoma
• Cemertifying firoma
• Calcifying epithelial odontogenic cyst
• Central giant cell granuloma.

Question 106. Define odontogenic myxoma.
Answer. Odontogenic myxoma is an aggressive, intraosseous neoplasm, which is derived from embryonic odontogenic mesenchyme.

Question 107. From which tissue odontogenic myxoma arises?
Answer. Odontogenic myxomas probably arise from the dental papilla or follicular mesenchyme.

Question 108. Describe the clinical appearances of odontogenic myxoma.
Answer. Clinically the lesion produces a slow growing but locally aggressive growth, which often causes painless swellings in the jaw. Few lesions assume huge size and cause displacement of the regional teeth, malocclusion and gross facial deformity.

Question 109. What are the radiological features of odontogenic myxoma?
Answer. The tumor often produces a multilocular radioluency in the jaw with ill-defied borders; which characteristically exhibits a spider-web-like or tennis racket-like appearance.

Question 110. How does the cut surface of odontogenic myxoma appears?
Answer. The cut surface of the tumor presents a loose gelatinous mass of tissue.

Question 111. Describe the histological appearances of odontogenic myxoma.
Answer. Histologically myxomas present widely separated, stellate-shaped cells within a loose mucoid, non-firilar, basophilic ground substance. The myxomatous tissue often invades widely into the surrounding normal bony trabaculae.

Question 112. Which lesions should be considered during differential diagnosis of odontogenic myxoma?
Answer.

• Central giant cell granuloma
• Aneurysmal bone cyst
• Chondromyxoid firoma
• Ameloblastoma
• Calcifying epithelial odontogenic tumor
• Hyperparathyroidism.

Question 113. What is the treatment of choice in odontogenic myxoma?
Answer. Radical surgery is the treatment of choice (as it is a locally aggressive tumor with infitrative growth pattern).

Question 114. What is a cementoma?
Answer. Cementoma is a relatively uncommon odontogenic neoplasm, occurring in relation to the periapical bone and cementum at the root apex of vital teeth.

Question 115. What is the other name of cementoma?
Answer. Periapical cemental dysplasia.

Question 115a. What is the common age of occurrence of cementoma?
Answer. Generally occurs in the third and forth decade of life.

Question 116. In which sex is more commonly seen?
Answer. Females are affected far more commonly than males.

Question 117. What is the most common site of occurrence of cementoma?
Answer. It occurs mostly in relation to the mandibular anterior teeth; although maxillary teeth are also sometimes affected.

Question 118. In cementoma, is the lesion symptomatic?
Answer. The lesions are mostly asymptomatic and are detected only incidentally.

Question 119. In cementoma, the associated teeth are vital or non-vital?
Answer. The associated teeth are always vital.

Question 120. What are the different stages of development of cementoma?
Answer. Cementomas generally develop in three stages:

• Osteolytic stage
• Cementoblastic stage
• Mature stage.

Question 121. Describe the radiological appearance of cementoma in its three different stages of development.
Answer.

• Stage I (initial osteolytic stage): A small, well-defined, radiolucent area is seen near the apex of the involved tooth. The radiolucency is always found to be in continuation with the periodontal ligament space
• Stage II (cementoblastic stage): The lesion presents a radiolucent area near the root apex containing multiple small radiopaque foci
• Stage III (mature stage): A well-defined radiopaque mass is seen at the root apex,being surrounded by a thin radiolucent zone.

Question 122. Describe the histological appearances of cementoma at different stages of its development.
Answer.

• Cementoma stage I: Cemental tissue at the root apex of the involved teeth are destroyed along with the periapical alveolar bone and are replaced by firous connective tissue
• Cementoma stage II (cementoblasts stage): Formation of small amorphous mass of immature cemental tissue occurs at the root apex
• Cementoma stage III (mature stage of cementoma): The entire fibrous tissue at the root apex is replaced by a large mass of mature cemental tissue.

Question 123. What must be done before making any conclusive diagnosis of cementoma?
Answer. Vitality test of the involved teeth.

Question 124. Which lesions must be kept in mind during differential diagnosis of cementoma?
Answer.

• Periapical granuloma of tooth
• Periapical cyst
• Condensing osteitis
• Bony artifacts.

Question 125. What is the treatment of cementoma?
Answer. No treatment is required for cementoma.

Question 126.Defie familial gigantiform cementoma.
Answer. Familial gigantiform cementoma is a rare benign condition, which appears to represent a dysplastic or hamartomatous malformation of the cementum forming tissues.

Question 127. Familial gigantiform cementoma is what type of a disorder?
Answer. It is a genetic disorder.

Question 128. Familial gigantiform cementoma occurs at what age and in which sex it is more common?
Answer. It occurs during the childhood and is seen more frequently among females.

Question 129. Describe the clinical features of familial gigantiform cementoma.
Answer. Initially familial gigantiform cementoma presents slow growing painless expansile jaw swelling. Gradually the lesion increases in size and causes facial asymmetry. Secondary infection may occur in the lesion, which results in pain and even formation of intraoral or extraoral pus discharging sinuses.

Question 130. Describe the radiographic appearance of familial gigantiform cementoma.
Answer. Radiograph reveals a large, sometimes massive expansile lesion of mixed radiolucency in the jaw with well-defined margins.

Question 131. What is the histological appearance of familial gigantiform cementoma?
Answer. Histologically, the lesion presents a loose vascular tissue stroma containing large irregular scattered masses of dense mineralized tissue resembling acellular cementum.

Question 132. What is a cementoblastoma?
Answer. Cementoblastoma is a rare benign odontogenic neoplasm arising from the cementoblast cells.

Question 133. Where these lesions are found?
Answer. The tumors develop as an irregular rounded mass in continuity with the apical cementum of a vital molar or premolar tooth root.

Question 134. What is the other name of cementoblastoma?
Answer. True cementoma.

Question 135. Describe the clinical appearance of cementoblastoma.
Answer.

• Cementoblastoma often produces a slow enlarging, bony hard swelling of the jaw with displacement of the regional teeth
• A low-grade intermittent pain may be present, which is felt more often when the area is palpated. The lesion is often attached to the apical third of a vital mandibular premolar or molar tooth
• A dull sound is produced upon percussion of the involved tooth.

Question 136. How cementoblastoma appears radiographically?
Answer. Radiographically it presents a large, dense, radiopaque mass being attached to one or more vital tooth roots and at the periphery it is surrounded by a thin zone of radiolucency.

Question 137. Describe the hostological appearance of cementoblastoma.
Answer.

• It shows a large amorphous cemental tissue mass, which is fused with the root of involved tooth and is surrounded by a thin soft tissue capsule
• At the center of the tumor, numerous irregularly placed trabeculae of cementum are present, each one bordered at the periphery by cementoblast or cementoblast-like cells and they also exhibit multiple basophilic reversal lines.
• Individual trabeculae are bordered at the periphery by cementoblast or cementoblast-like cells.

Question 138. Which lesions should be considered during the differential diagnosis of cementoblastoma?
Answer.

• Osteoblastoma
• Osteoid osteoma
• Paget’s disease of bone
• Osteosarcoma
• Focal sclerosing osteomyelitis.

Question 139. What is malignant ameloblastoma?
Answer. Malignant ameloblastomas is a cytologically benign lesion, which shows metastasis.

Question 140. Malignant ameloblastomas can metastasize to which organs?
Answer. Metastasis usually occurs to distant lymph nodes and the lung.

Question 141. What is ameloblastic carcinoma?
Answer. Ameloblastic carcinoma is a true malignant neoplasm of odontogenic epithelial tissue, in which the epithelial components of the lesion are cytologically malignant.

Question 142. What is odontogenic carcinoma?
Answer. These are aggressive and destructive intraosseous lesions consisting of poorly differentiated epithelial cells and clear cells in a pattern that is reminiscent of early odontogenesis.

Question 143. What is an odontogenic sarcoma?
Answer. These are rare aggressive malignant odontogenic neoplasms, in which the epithelial components are non-neoplastic but the mesenchymal components exhibit features of firosarcoma.

Question 144. What is a clear cell odontogenic tumor?
Answer. Clear cell odontogenic tumor is a locally aggressive, rare odontogenic neoplasm of epithelial cell origin.

Question 145. Why this tumor is named clear cell odontogenic tumor?
Answer. Because histologically this neoplasm is poorly circumscribed and it consists of sheets of odontogenic epithelial cells with clear cytoplasm and centrally placed nuclei.