Solitary plasmacytoma.

A retrospective review is presented of nine patients presenting with solitary plasmacytoma. Between 1963 and 1980, these patients were treated with radiation at the Department of Radiation Oncology, University of Louisville. Criteria for admission to this particular study include (1) a solitary focus of plasmacytoma proven by biopsy, (2) normal bone marrow findings (less than 10% plasma cells), and (3) no evidence of disseminated disease. In six patients the primary site was osseous, and in three extramedullary, two of which were located in the nasopharynx and nasal cavity and the third in the stomach. All of the extramedullary plasmacytomas are disease free for periods ranging from 4 to 10 years. Of the six patients with osseous lesions, two developed multiple myeloma in 2 and 3 years, two are NED (No Evidence of Disorder) after 9 years, one died of intercurrent disease, and the remaining patient was NED for 2 years, after which he was lost to follow-up. These results suggest the more favorable prognosis of extramedullary plasmacytoma and support the theory that the solitary plasmacytoma of bone and extramedullary plasmacytoma are distinct disease entities.