Perineal infiltration by plasma cells in a patient with multiple myeloma. A rare presentation.

The case history of a 39-year-old man suffering from multiple myeloma is presented. During his illness he developed congestive cardiomyopathy, possibly due to amyloidosis, and a single perineal plasma cell infiltrate, resembling a perianal fistula. This diagnosis should be considered in patients with multiple myeloma suffering from perineal lesions.