Question

A 30 year old woman came with flaccid bullae on her skin which were easy to rupture. Biopsy of the lesion revealed a suprabasal split. What is the most likely diagnosis?

• A. Pemphigus vegetans
• B. Pemphigus vulgaris
• C. Pemphigus foliaceous
• D. Erythema multiforme

Hint:

The level of the epidermal split on biopsy is the key to diagnosing pemphigus subtypes.

Answer 1

The Correct Option is B

Clinical scenario: 30-year-old woman, flaccid bullae, easy to rupture, biopsy shows suprabasal split.

Diagnosis: Pemphigus vulgaris

Pathogenesis: IgG autoantibodies against desmoglein 3 (Dsg3) -- a desmosomal cadherin -- disrupt keratinocyte-to-keratinocyte adhesion. This results in acantholysis (loss of cohesion between keratinocytes) just above the basal layer.

Histology hallmarks:
- Suprabasal acantholysis
- Basal cells remain on basement membrane in a "tombstone" arrangement
- Acantholytic cells (Tzanck cells) in blister cavity

Comparison:
- Pemphigus foliaceous: subcorneal split (higher up), anti-Dsg1, no mucosal involvement
- Pemphigus vegetans: suprabasal like PV but with vegetating lesions in flexures
- Erythema multiforme: subepidermal, target lesions, different immunopathology

Key clinical clue: Flaccid bullae + easy rupture + suprabasal split = Pemphigus vulgaris

\[\boxed{\text{Pemphigus vulgaris}}\]