Pemphigus Vulgaris — MFDS Part 1 MCQ

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ModerateOral PathologyPemphigus VulgarisMFDS Part 1

A 52-year-old patient has several weeks of painful, widespread oral erosions involving both keratinised and non-keratinised mucosa, followed by the development of flaccid skin blisters. Biopsy from the edge of an intact lesion shows a suprabasal intraepithelial split with acantholysis. What is the most likely diagnosis?

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Correct answer: D — Pemphigus vulgaris

The diagnosis is **pemphigus vulgaris**. The decisive finding is a suprabasal intraepithelial split caused by acantholysis, matching the widespread painful oral erosions and flaccid cutaneous blisters. Pemphigus vulgaris is mediated mainly by IgG autoantibodies to desmoglein 3; mucocutaneous disease commonly also involves desmoglein 1. Direct immunofluorescence typically shows intercellular IgG and C3. Mucous membrane pemphigoid produces subepithelial separation rather than acantholysis and may cause scarring, particularly at ocular sites. Erythema multiforme is an acute reaction pattern often associated with lip crusting and target lesions. Lichen planus shows interface mucositis, while herpetic gingivostomatitis has an acute febrile presentation and viral cytopathic changes. Therefore, A is the unique best answer.

Reference: Indian Journal of Dermatology, Histopathology of Pemphigus Vulgaris Revisited, 2020. https://pubmed.ncbi.nlm.nih.gov/33208597/