Muscle and nerve involvement in granulomatous mycosis fungoides

Occasional cases of peripheral neuropathy have been reported in classic mycosis fungoides. A rare variant of mycosis fungoides is the granulomatous form. We describe the occurrence of myopathy and peripheral neuropathy in a young woman who had skin lesions since the age of 12 years. At the age of 20 years they were diagnosed as granulomatous mycosis fungoides. The skin lesions resolved with interferon therapy and radiation. She then presented with cardiac and pulmonary symptoms and signs that were initially thought to be due to sarcoidosis or systemic vasculitis. A nerve and muscle biopsy showed granulomatous mycosis fungoides. To our knowledge, involvement of muscle and nerve by granulomatous mycosis fungoides has not been reported previously. Early reports suggested a favorable prognosis for the granulomatous subtype of mycosis fungoides. Based on a literature review and the course in our case, however, granulomatous mycosis fungoides seems to be an indicator of aggressive disease and ultimately a poor prognosis.