Unusual cutaneous dissemination of a tropical fish tank granuloma.

A patient with an unusual disseminated tropical fish tank granuloma is presented. The infection manifested first as red, subcutaneous nodules of the right hand and forearm. During subsequent days and weeks, nodules appeared on the left arm, on the ventral and dorsal thorax, on one leg, and the face. The diagnosis was based on, in addition to the history and the clinical aspects, a positive reaction to intracutaneous testing with a specific Mycobacterium marinum antigen and on the histologic examination of biopsy specimens. The larger nodules were treated with excision. Smaller nodules disappeared spontaneously after the larger ones had been surgically removed.