Pathology · single question
What is the DIAGNOSIS?
Show answer and explanation
Correct answer: A. Mucous membrane pemphigoid
Mucous membrane pemphigoid (MMP): subepithelial split, positive Nikolsky, perilesional IgG/IgA/C3 along BMZ on DIF, desquamative gingivitis, may involve eyes. Pemphigus vulgaris: intraepithelial split, acantholysis, Tzanck cells, IgG on cell surfaces (intercellular). Erythema multiforme: target lesions, often lip crusting. Key: MMP = basement membrane = subepithelial.