Primary extramedullary plasmacytoma of submaxillary lymph node.

A case of extramedullary plasmacytoma originating in the left submaxillary lymph node in a 63-year-old man was reported. The diagnosis of plasmacytoma was made on the basis of a monoclonal proliferation of IgG, K type of plasma cells by means of immune antibody staining. About 70% of extramedullary plasmacytoma cases have been reported to have a primary lesion in the upper respiratory tract and the oral cavity with cervical lymph node metastases in 8-30%. The present case was considered to be of submaxillary lymph node origin in view of failure of various examinations to detect lesions in the oral cavity and the upper part of the respiratory tract.