Secondary extramedullary plasmacytoma involving the pancreas.

Extramedullary plasmacytoma is a rare variant of plasma cell tumor involving organs outside the bone marrow. The vast majority of extramedullary plasmacytomas present as a secondary tumor of systemic myelomatosis of the bone marrow. We experienced a patient with extramedullary plasmacytomas of the head and tail of the pancreas presenting as secondary masses from extramedullary plasmacytoma of the maxillary sinus that had been treated 5 years previously. A 38-year-old Japanese man had undergone radiation therapy for an extramedullary plasmacytoma of the maxillary sinus 5 years before the current presentation. He experienced severe upper abdominal pain in November 1999, when laboratory data showed elevation of the serum amylase level. Computed tomography showed two isodensity masses, in the head and tail of the pancreas. Angiography showed two hypervascular masses, one in the head and the other in the tail of the pancreas, and encasement of the portal vein trunk junction. Laparotomy was performed, with the tentative diagnosis of extramedullary plasmacytoma of the pancreas, in order to obtain a definite diagnosis. Intraoperative biopsy revealed that the two pancreatic masses were extramedullary plasmacytomas. External radiation therapy was performed after the operation. When a pancreatic mass is noticed in patients with a history of plasmacytoma, secondary extramedullary plasmacytoma of the pancreas should be considered as a differential diagnosis.