Primary small bowel plasmacytoma with intracellular fibrils.

This is a report of a rare plasma cell tumor, an extramedullary plasmacytoma arising in the small bowel. The tumor first occurred in the jejunum without evidence of multiple myeloma. One year later, classical signs of multiple myeloma appeared. The rarity and unusual course of this tumor plus the finding of intracellular fibrils make the case worthy of note.