Extramedullary plasmacytoma of the jejunum.

A case of extramedullary plasmacytoma (EMP) of the jejunum, an uncommon neoplasia, is reported. A 56-year-old Japanese woman who experienced intermittent upper abdominal pain and weight loss had a large movable mass in the upper abdomen. The mass was hypervascular in an angiographic study and positive for gallium-67 citrate scintigraphy. Immunoelectrophoresis showed the presence of an M-component of immunoglobulin (Ig) A-lambda in the serum. It was identified as an EMP immunohistochemically positive for IgA-lambda. This M-component disappeared after resection and chemotherapy. The clinical features of this rare neoplastic disorder are discussed.