Emergence of leprosy in a patient with mycosis fungoides.

A patient with mycosis fungoides that had progressed to tumor stage responded to chemotherapy and electron beam treatment, but 6 years later a peripheral neuropathy, extensive plaques, erythroderma, and enlarged pinnae containing acid-fast organisms developed while he was being treated with photopheresis. The skin lesions cleared with administration of rifampin and dapsone, but a reversal reaction biopsy specimen showed features of both mycosis fungoides and leprosy. This case raises the question of whether there may be an association between mycosis fungoides and leprosy.