Extramedullary plasmacytoma of the colon.

Multiple myeloma with extramedullary plasmacytoma is unusual, but associated gastrointestinal involvement is even rarer. A case with initial presentation as solitary plasmacytoma of the clavicle and subsequent lesions in the maxillary sinus, skin, and ascending colon is reviewed. The variable radiographic features of plasmacytoma of the colon are discussed, whether occurring as a solitary finding or in a patient with multiple myeloma.