Pathology · patient case question
What is the appropriate biopsy technique for establishing the diagnosis?
Patient case: Gums That Peel
Patient: 61-year-old female
Chief Complaint: “My gums peel away and I keep getting blisters that pop and leave raw spots.”
Background: Symptoms present for 5 months and worsening. Difficulty eating due to pain. She also reports persistent dry mouth. No known autoimmune disease.
Medications: Sertraline · Oxybutynin · Loratadine
Vital Signs: BP 130/80 mmHg · HR 76 bpm · RR 16 · T 98.6°F
Findings: Diffuse erythematous, desquamating attached gingiva in all quadrants. Flaccid bullae on the buccal mucosa that rupture readily, leaving ragged, painful ulcers. Firm lateral pressure on clinically uninvolved mucosa induces epithelial sloughing. Reduced salivary pooling; multiple new cervical carious lesions since her last visit.
Show answer and explanation
Correct answer: C. Perilesional incisional biopsy with a portion submitted for direct immunofluorescence
- A. Incorrect. Excision of the entire involved gingiva is unnecessarily destructive and pointless in a condition that is diffuse and immune-mediated rather than localized.
- B. Incorrect. The center of an ulcer contains only necrotic debris and granulation tissue. The epithelium that carries the diagnostic information has already been lost.
- C. Correct. The immunoreactants are deposited in intact epithelium, so the specimen must include clinically normal-appearing tissue adjacent to the lesion. Submit one portion in formalin for routine histology and a second in Michel’s medium for direct immunofluorescence, which in pemphigus vulgaris shows an intercellular fishnet pattern of IgG and C3.
- D. Incorrect. Cytology samples surface cells only. Tzanck cells may be seen, but it cannot demonstrate the level of epithelial separation or the immunofluorescence pattern, so it is not diagnostic.
Note: The positive Nikolsky sign described here — epithelial sloughing on lateral pressure over clinically normal mucosa — is a hallmark of the vesiculobullous diseases and is a strong clue on any board question.