A 60-year-old man has had slowly progressive erythematous scaling patches and plaques on the trunk for 6 years, unresponsive to topical steroids. Skin biopsy shows epidermotropism of atypical lymphocytes with convoluted nuclei forming intraepidermal collections. Blood count and peripheral smear are unremarkable. Most likely diagnosis?
- A Primary cutaneous CD30-positive anaplastic large cell lymphoma
- B Sézary syndrome
- C Mycosis fungoides ✓
- D Subcutaneous panniculitis-like T-cell lymphoma
Correct answer: C. Mycosis fungoides
Explanation
Longstanding patches and plaques with epidermotropism of cerebriform lymphocytes forming Pautrier microabscesses establish mycosis fungoides. Sézary syndrome requires generalized erythroderma with significant circulating neoplastic cells and an inverted CD4 to CD8 ratio, none of which is present here. Primary cutaneous CD30-positive anaplastic large cell lymphoma appears as ulcerating solitary or few tumours, and subcutaneous panniculitis-like T-cell lymphoma infiltrates subcutaneous fat rather than the epidermis.
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.