Free DMD Oral Pathology and Diagnosis Questions and Answers — Questions and Answers
Question 1: A 45-year-old male presents with a painless, multilocular radiolucency in the posterior mandible, discovered on a routine panoramic radiograph. The lesion exhibits a 'soap bubble' appearance. Tooth resorption and cortical expansion are noted. Which of the following is the most likely diagnosis?
- Odontogenic Keratocyst (OKC)
- Ameloblastoma (Correct answer)
- Central Giant Cell Granuloma (CGCG)
- Cherubism
Correct answer: Ameloblastoma
Ameloblastoma is the most common odontogenic tumor, frequently presenting as a multilocular, 'soap bubble' or 'honeycomb' radiolucency in the posterior mandible of middle-aged adults. It is known for its locally aggressive behavior, often causing significant bone expansion and root resorption of adjacent teeth. While OKC can also be multilocular, it is less likely to cause prominent expansion and root resorption. CGCG typically occurs in a younger age group and often anterior to the first molars. Cherubism is characterized by bilateral, symmetrical jaw involvement in children.
Question 2: A 60-year-old female patient complains of painful oral erosions and blisters that have been present for several months. Intraoral examination reveals irregular, fragile bullae and widespread ulcerations on the buccal mucosa and palate. A positive Nikolsky's sign is elicited. Histopathological examination of a biopsy specimen is most likely to show:
- Subepidermal separation with an eosinophil-rich infiltrate
- Hyperkeratosis with a band-like lymphocytic infiltrate
- Intraepithelial separation (acantholysis) just above the basal cell layer (Correct answer)
- Acanthosis with elongated rete ridges and Munro's microabscesses
Correct answer: Intraepithelial separation (acantholysis) just above the basal cell layer
Pemphigus vulgaris is an autoimmune blistering disease where autoantibodies target desmosomes, leading to a loss of cell-to-cell adhesion (acantholysis). Histologically, this manifests as an intraepithelial split, characteristically located just above the basal cell layer (suprabasal), creating blisters. The basal cells remain attached to the underlying connective tissue, sometimes described as a 'row of tombstones'. The presence of acantholytic Tzanck cells within the blister is also a key feature.
Question 3: Which of the following oral lesions has the highest potential for malignant transformation?
- Homogeneous Leukoplakia
- Oral Lichen Planus
- Erythroplakia (Correct answer)
- Oral Hairy Leukoplakia
Correct answer: Erythroplakia
Erythroplakia, a red patch that cannot be clinically or pathologically diagnosed as any other condition, has the highest malignant potential among oral precancerous lesions. A very high percentage of erythroplakias show severe dysplasia, carcinoma in situ, or invasive squamous cell carcinoma at the time of biopsy. While some leukoplakias (especially non-homogeneous or erythroleukoplakia) are precancerous, erythroplakia is considered much more ominous. Oral lichen planus has a much lower, though still debated, risk. Oral hairy leukoplakia, caused by the Epstein-Barr virus, is not considered a premalignant lesion.
Question 4: A 22-year-old male is referred by his orthodontist due to multiple impacted supernumerary teeth and several dense, well-defined radiopacities in the mandible and maxilla seen on a panoramic radiograph. The patient also has multiple sebaceous cysts on his back. These findings are highly suggestive of which systemic condition?
- Cleidocranial Dysplasia
- Sjögren's Syndrome
- Cherubism
- Gardner Syndrome (Correct answer)
Correct answer: Gardner Syndrome
Gardner syndrome is an autosomal dominant condition characterized by a triad of intestinal polyposis, multiple osteomas (especially in the jaws and skull), and soft tissue tumors like epidermoid or sebaceous cysts. Dental anomalies, including multiple impacted and supernumerary teeth and odontomas, are also very common features. The presence of multiple osteomas and dental abnormalities often precedes the diagnosis of intestinal polyps, which have a near 100% risk of malignant transformation.
Question 5: A 55-year-old female patient presents with severe xerostomia, rampant cervical and root caries, and a fissured tongue. She also complains of dry eyes. A labial salivary gland biopsy is performed to confirm a suspected diagnosis. Which histologic finding would be most characteristic of Sjögren's Syndrome?
- Squamous metaplasia of ductal epithelium
- Fibrosis and fatty infiltration of the acini
- Focal lymphocytic sialadenitis with a focus score of ≥1 (Correct answer)
- Mucous extravasation phenomenon with granulation tissue
Correct answer: Focal lymphocytic sialadenitis with a focus score of ≥1
The hallmark histopathologic feature of Sjögren's Syndrome in a minor salivary gland biopsy is focal lymphocytic sialadenitis. A diagnosis is supported by finding dense aggregates of 50 or more lymphocytes and plasma cells (a focus) adjacent to normal-appearing mucous acini. A focus score of ≥1 focus per 4 mm² of glandular tissue is considered a positive finding for the diagnosis.
Question 6: A patient presents with asymptomatic, white, corrugated lesions along the lateral borders of the tongue that cannot be wiped off. The patient is known to be immunosuppressed. Which of the following is the most likely diagnosis?
- Oral Hairy Leukoplakia (Correct answer)
- Candidiasis (Thrush)
- Lichen Planus
- Frictional Keratosis
Correct answer: Oral Hairy Leukoplakia
Oral hairy leukoplakia is caused by the Epstein-Barr virus (EBV) and typically presents as asymptomatic, white, vertically corrugated or 'hairy' plaques on the lateral borders of the tongue. It is most commonly seen in individuals with compromised immune systems, such as those with HIV/AIDS. Unlike candidiasis, these lesions cannot be scraped off. Lichen planus can appear similar but often has a reticular (Wickham's striae) pattern and can be symptomatic. Frictional keratosis would correspond directly to an area of irritation.
Free DMD Oral Pathology and Diagnosis Questions and Answers
A 45-year-old male presents with a painless, multilocular radiolucency in the posterior mandible, discovered on a routine panoramic radiograph.
The lesion exhibits a 'soap bubble' appearance.
Tooth resorption and cortical expansion are noted.
Which of the following is the most likely diagnosis?