A 40-year-old man presents with flaccid, easily ruptured blisters in the mouth and on the skin. Nikolsky sign is positive. Biopsy shows an intraepidermal blister with acantholysis (loss of intercellular bridges) just above the basal layer, with basal cells remaining attached to the dermis ('tombstone' pattern). Which immunofluorescence pattern confirms the diagnosis?

• A Linear IgG along the dermoepidermal junction
• B Granular IgA deposits in dermal papillae
• C Granular C3 at the dermoepidermal junction
• D Intercellular (fishnet/chicken-wire) IgG deposits throughout the epidermis ✓

Explanation

The clinical and histologic features describe pemphigus vulgaris (PV), characterized by autoantibodies against desmoglein 3 (and sometimes desmoglein 1), causing acantholysis with suprabasal blister formation and the tombstone pattern of residual basal cells. Direct immunofluorescence in PV shows the pathognomonic intercellular (fishnet or chicken-wire) pattern of IgG deposits outlining individual keratinocytes throughout the epidermis. Linear IgG at the BMZ is seen in bullous pemphigoid; granular IgA in papillae is the hallmark of dermatitis herpetiformis.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.