A 62-year-old man has slowly enlarging scaly erythematous skin patches on the trunk that have progressed over five years to raised plaques and now cutaneous nodules. Skin biopsy shows atypical CD4+ T cells infiltrating the epidermis and forming collections within the stratum corneum layer. What is the diagnosis?

• A Cutaneous marginal zone lymphoma
• B Adult T-cell leukemia/lymphoma
• C Anaplastic large cell lymphoma
• D Mycosis fungoides ✓

Explanation

The indolent patch-to-plaque-to-tumor progression over years plus epidermotropism of atypical CD4+ T cells forming Pautrier microabscesses within the epidermis is diagnostic of mycosis fungoides, the commonest cutaneous T-cell lymphoma. Adult T-cell leukemia/lymphoma runs a far more aggressive systemic course with hypercalcemia and HTLV-1 association, and the other options lack epidermotropic Pautrier collections as their hallmark.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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