AGD Oral Pathology and Diagnosis 2 — Questions and Answers
Question 1: A 45-year-old patient presents with a painless, slow-growing swelling of the posterior mandible. Radiograph shows a unilocular radiolucency with a scalloped border around impacted third molar roots. What is the most likely diagnosis?
- Dentigerous cyst
- Ameloblastoma
- Odontogenic keratocyst (Correct answer)
- Radicular cyst
Correct answer: Odontogenic keratocyst
Odontogenic keratocysts classically present as unilocular or multilocular radiolucencies with scalloped borders, often associated with impacted teeth, and have a high recurrence rate.
Question 2: Which of the following is the MOST characteristic microscopic feature of an ameloblastoma?
- Orthokeratinized stratified squamous epithelium
- Peripheral palisading of columnar cells with reversed polarity and stellate reticulum (Correct answer)
- Ghost cell keratinization
- Hyalinized stroma with calcifications
Correct answer: Peripheral palisading of columnar cells with reversed polarity and stellate reticulum
Ameloblastoma is characterized histologically by peripheral palisading of columnar ameloblast-like cells with nuclei displaced away from the basement membrane (reversed polarity) surrounding a stellate reticulum-like center.
Question 3: A biopsy of a white lesion on the floor of the mouth reveals moderate epithelial dysplasia. Which feature is NOT a criterion for epithelial dysplasia?
- Loss of polarity of basal cells
- Drop-shaped rete ridges
- Increased mitotic figures in the superficial layers
- Intercellular edema (spongiosis) (Correct answer)
Correct answer: Intercellular edema (spongiosis)
Spongiosis (intercellular edema) is a feature of inflammatory conditions like eczema, not a criterion for epithelial dysplasia.
Question 4: Necrotizing sialometaplasia most commonly affects which location and is most frequently confused with which malignancy?
- Parotid gland; adenoid cystic carcinoma
- Hard palate; mucoepidermoid carcinoma (Correct answer)
- Sublingual gland; acinic cell carcinoma
- Buccal mucosa; squamous cell carcinoma
Correct answer: Hard palate; mucoepidermoid carcinoma
Necrotizing sialometaplasia typically presents as a crater-like ulcer on the hard palate and can be mistaken for mucoepidermoid carcinoma due to squamous metaplasia of salivary ducts.
Question 5: A 60-year-old smoker presents with a red, velvety patch on the floor of the mouth that cannot be wiped off. Biopsy shows carcinoma in situ. What is the clinical diagnosis?
- Erythroplakia (Correct answer)
- Erythema multiforme
- Candidal erythematous lesion
- Median rhomboid glossitis
Correct answer: Erythroplakia
Erythroplakia is a red velvety mucosal patch that cannot be attributed to any other condition and carries the highest risk of malignant transformation among oral potentially malignant disorders.
Question 6: Which odontogenic tumor is derived from remnants of the dental lamina and is characterized by a 'string of pearls' arrangement of epithelial islands with calcifications?
- Adenomatoid odontogenic tumor
- Calcifying epithelial odontogenic tumor (Correct answer)
- Calcifying odontogenic cyst
- Ameloblastic fibroma
Correct answer: Calcifying epithelial odontogenic tumor
The calcifying epithelial odontogenic tumor (Pindborg tumor) shows polyhedral epithelial cells with concentric calcifications (Liesegang rings) and amyloid-like material in the stroma.
Question 7: A patient presents with multiple radiopaque masses in the jaw associated with supernumerary teeth, epidermoid cysts of the skin, and osteomas. What syndrome does this suggest?
- Gorlin-Goltz syndrome
- Gardner syndrome (Correct answer)
- Cowden syndrome
- Peutz-Jeghers syndrome
Correct answer: Gardner syndrome
Gardner syndrome is an autosomal dominant condition caused by APC gene mutations featuring intestinal polyposis, osteomas, epidermoid cysts, and supernumerary/impacted teeth.
AGD Oral Pathology and Diagnosis 2
A 45-year-old patient presents with a painless, slow-growing swelling of the posterior mandible.
Radiograph shows a unilocular radiolucency with a scalloped border around impacted third molar roots.
What is the most likely diagnosis?