Clinical outcome of extramedullary plasmacytoma

The aim of this study was a retrospective analysis of the presenting features of extramedullary plasmacytoma, its response to therapy and its clinical course.

Forty-six cases diagnosed between August 1970 and June 1993 were carefully reviewed. The follow-up was continued until June 1998 and the median observation time was 118 months.

The disease was most frequently localized in the upper airways (37/46; 80%), with the mass limited to a single site in all but seven patients in whom two contiguous sites were involved. Other localizations were the lymph nodes, thyroid, skin, stomach, and brain. The clinical symptoms were related to the site of presentation, and the median time between appearance and diagnosis was 7.5 months. The median age at diagnosis was 55 years (range 16-80), with 14 patients (30%) being under 50 years old. The disorder was approximately twice as common in males as in females. Ten patients (21%) had a monoclonal component. The therapeutic strategy varied, although the most frequent form of treatment was local radiotherapy. Thirty-nine patients (85%) achieved complete remission (CR), five (11%) a partial remission (PR) and two (4%) did not respond to therapy (NR). Local recurrence (LR) or recurrence at other sites (ROS) occurred in 7.5% and 10%, respectively. Seven patients (15%) developed multiple myeloma (MM), characterized by multiple sites of osteolysis in almost all cases with soft tissue involvement in some of them. The 15 year survival rate was 78%.

This review of a relatively large series of patients confirms the favorable prognosis of EMP when treated locally by irradiation and/or surgery.