Plasmacytoma of lymph nodes.

A case of primary plasmacytoma in a lymph node accompanied by IgG Kappa paraproteinemia is described. Eight months after the plasmacytoma's removal, the paraprotein was undetectable in the serum and the patient has remained well for a year. Abundant crystalline inclusions were present in the tumor and the immunoperoxidase technique was used to show that these consisted of monotypic immunoglobulin are were contained predominantly within macrophages. Reported cases of plasmacytoma in lymph nodes are reviewed and the natural history of this group of tumor is discussed.