Extramedullary plasmacytoma of the small intestine: a case report studied with electron microscopy and immunoperoxidase technique.

A well-documented case of solitary extramedullary plasmacytoma located in the small intestine is presented. The patient underwent local resection of the tumor, and shows no signs of local recurrence or dissemination of the disease after a five-year follow-up. The pathologic nature of plasma cell tumors is discussed, and it is concluded that the demonstration of intracytoplasmatic immunoglobulin is essential for the exact classification of plasma cell neoplasms.