A 55-year-old patient develops erythroderma (>90% BSA erythema and scaling) over 6 weeks. He has pruritus, edema of legs, nail dystrophy, and a new lymphadenopathy. A skin biopsy is taken. Which histopathological feature would most strongly suggest mycosis fungoides as the underlying cause rather than psoriasis?

• A Acanthosis and elongated rete ridges
• B Pautrier microabscesses in the epidermis ✓
• C Munro microabscesses in the stratum corneum
• D Spongiosis with eosinophilic infiltrate

Explanation

Pautrier microabscesses — collections of atypical T lymphocytes within the epidermis — are the hallmark histopathological finding of mycosis fungoides (cutaneous T-cell lymphoma). They are not seen in psoriasis. Munro microabscesses (neutrophils in stratum corneum) are characteristic of psoriasis. Acanthosis with elongated rete ridges also favours psoriasis. Erythrodermic MF (Sézary syndrome variant) requires histological and immunophenotypic confirmation to distinguish from other causes of erythroderma.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.