A 60-year-old man has scaly erythematous plaques in bathing-trunk distribution that progressed over years despite topical steroids. Biopsy shows atypical mononuclear cells lining up along the basal layer with clear halos around them, and small intraepidermal collections of these convoluted lymphocytes. The intraepidermal collections are termed:

• A Kogoj spongiform pustules
• B Pautrier microabscesses ✓
• C Munro microabscesses
• D Spongiosis with neutrophils

Explanation

Mycosis fungoides shows epidermotropism of atypical cerebriform T lymphocytes that form small clusters within the spongiotic epidermis called Pautrier microabscesses, with perinuclear halos. Munro microabscesses are neutrophil aggregates in the stratum corneum of psoriasis, and Kogoj pustules are neutrophilic spongiform collections also seen in psoriasis. The haloed basal alignment of atypical lymphocytes further supports mycosis fungoides.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.