RESUMEN
Sézary syndrome is a rare aggressive leukemic variant of primary cutaneous T-cell lymphoma, typically presenting with erythroderma, lymphadenopathy, and an atypical clonal T-cell population. Though it often involves the spleen and liver, we report a case of Sézary syndrome with renal involvement that was treated successfully. Visceral involvement confers a poor prognosis requiring systemic treatment. The patient we describe was a 66-year-old man who was referred from Dermatology services for deteriorating kidney function. Polymerase chain reaction of genomic DNA from skin and kidney biopsies confirmed a clonal T-cell population matching a population isolated in peripheral blood. The patient was treated initially with alemtuzumab, which led to a significant improvement in kidney function, and he has subsequently received a successful allogeneic stem cell transplant. This case represents a rare cause of decreased kidney function and highlights the role of biopsy in patients with suspected Sézary syndrome.