13‐cis‐retinoic acid induces cellular differentiation and durable remission in refractory cutaneous ki‐1 lymphoma

A 35‐year‐old man with refractory cutaneous Ki‐1 lymphoma was salvaged successfully with oral 13‐cis‐retinoic acid (1 mg/kg/day). He had a complete remission lasting for 20 months before a single nodule recurred on his skin. Excisional biopsy of the recurrent tumor revealed a distinct morphologic change, suggesting cellular differentiation toward a more benign phenotype. No significant side effects were noted except mild xerostomia, bone pain, and hyperlipidemia. The authors believe that 13‐cis‐retinoic acid should be considered in the treatment of cutaneous Ki‐1 lymphoma.