Pathology · single question
Erythematous gingiva with multiple areas of erosion (desquamative gingivitis) is most definitively diagnosed by:
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Correct answer: C. Direct immunofluorescence (DIF) biopsy
- A. Brush biopsy evaluates superficial dysplasia — not adequate for vesiculobullous disease diagnosis.
- B. Exfoliative cytology cannot differentiate between causes of desquamative gingivitis.
- C. Correct. Desquamative gingivitis (red, eroded gingiva) is most commonly caused by lichen planus, MMP, or PV. The gold standard for diagnosing these vesiculobullous conditions is DIRECT IMMUNOFLUORESCENCE (DIF) — a perilesional biopsy with fluorescent-labeled antibodies showing: PV = IgG fishnet pattern in epithelium; MMP = linear IgG/IgA at basement membrane; LP = fibrinogen at basement membrane.
- D. Serum labs (ELISA for desmoglein antibodies) support the diagnosis but DIF is more definitive and required for tissue diagnosis.