AGD Oral Diagnosis and Pathology 3 — Questions and Answers
Question 1: Erythroplakia of the oral mucosa carries a malignant transformation rate of approximately:
- 50% (Correct answer)
- 5%
- 25%
- 90%
Correct answer: 50%
Erythroplakia has a malignant transformation rate of approximately 50%, making it far more dangerous than leukoplakia.
Question 2: A teenager presents with a well-defined unilocular radiolucency surrounding the crown of an unerupted mandibular third molar. This most likely represents:
- Dentigerous cyst (Correct answer)
- Odontogenic keratocyst
- Ameloblastoma
- Central giant cell granuloma
Correct answer: Dentigerous cyst
A dentigerous (follicular) cyst forms around the crown of an unerupted tooth, presenting as a pericoronal radiolucency.
Question 3: Which oral manifestation is MOST characteristic of primary herpetic gingivostomatitis?
- Multiple small vesicles that rupture leaving painful ulcers with generalized gingival erythema (Correct answer)
- Single painless ulcer with indurated border
- White patches that wipe off leaving a bleeding surface
- Bullae on non-inflamed mucosa
Correct answer: Multiple small vesicles that rupture leaving painful ulcers with generalized gingival erythema
Primary HSV-1 infection produces multiple vesicles that rupture into painful ulcers accompanied by diffuse gingival erythema, fever, and lymphadenopathy.
Question 4: Melanotic macule of the lip differs from an oral melanoma primarily by:
- Lack of epithelial atypia and absence of junctional activity (Correct answer)
- Smaller size
- Lighter coloration
- Location on the vermilion border
Correct answer: Lack of epithelial atypia and absence of junctional activity
Melanotic macule shows increased melanin in basal cells without melanocyte atypia or junctional activity, distinguishing it from early melanoma.
Question 5: 'Soap bubble' or multilocular radiolucency in the posterior mandible of a young adult is the classic radiographic presentation of:
- Ameloblastoma (Correct answer)
- Odontogenic keratocyst
- Dentigerous cyst
- Lateral periodontal cyst
Correct answer: Ameloblastoma
Ameloblastoma classically presents as a multilocular soap-bubble or honeycomb radiolucency in the posterior mandible of adults in the third to fourth decade.
Question 6: A creamy white plaque on the buccal mucosa of an HIV-positive patient that wipes off leaving an erythematous base most likely represents:
- Pseudomembranous candidiasis (Correct answer)
- Hairy leukoplakia
- Traumatic ulcer
- Koplik spots
Correct answer: Pseudomembranous candidiasis
Pseudomembranous candidiasis (thrush) presents as removable white plaques on an erythematous base, especially common in immunocompromised patients.
Question 7: Calcifying epithelial odontogenic tumor (Pindborg tumor) is characterized histologically by:
- Amyloid-like material with Liesegang ring calcifications (Correct answer)
- Ghost cell keratinization
- Reverse polarization of nuclei in palisaded cells
- Enamel matrix deposition
Correct answer: Amyloid-like material with Liesegang ring calcifications
Pindborg tumor shows sheets of polyhedral epithelial cells with amyloid-like material and concentric Liesegang ring calcifications.
AGD Oral Diagnosis and Pathology 3
Erythroplakia of the oral mucosa carries a malignant transformation rate of approximately: