Clinical course of solitary extramedullary plasmacytoma

Background and purpose: Solitary extramedullary plasmacytoma (EMP) represen ts a rare category of malignant disease on which there are limited data in regard to diagnosis, staging and natural history. This study attempted to c larify the clinical course of solitary extramedullary plasmacytoma after ra diation or surgical therapy given with curative intent. Materials and methods: The diagnosis was based on a mass of clonal plasma c ells separate from bone or bone marrow without evidence of occult disease e lsewhere. Between 1963 and 1996, 22 previously untreated patients with an E MP were diagnosed. Disease presented in the head or neck in 86%, usually in the nasal cavity (NC) or maxillary sinus (MS), and in these areas local bo ne destruction was found in 10 of 11 patients. Among all patients, serum my eloma protein was present in three patients (14%) and Bence Jones protein a lone was found in two patients (9%). Radiation therapy was the sole treatme nt for 18 of 22 patients, and the median radiotherapy dose was 50 Gy (range , 40-60 Gy); five of seven patients with an EMP of oral cavity (OC), oropha rynx (OP), nasopharynx (NP), parotid or larynx also received elective neck irradiation. Two patients underwent surgery plus postoperative irradiation of a plasmacytoma of the sigmoid colon or pleura, and two patients had rese ction alone of a plasmacytoma of the colon or cervical lymph node. Results: Local control was achieved in 21 of 22 patients (95%), and disease never recurred in regional nodes. Disappearance of myeloma protein occurre d in three of five patients with an evaluable abnormality. Multiple myeloma developed in seven patients (32%), all within 5 years. The 5-year rate of freedom from progression to multiple myeloma was 56% and the median surviva l was 9.5 years. Conclusion: Radiation therapy achieved excellent locoregional control of EM P with an approximate cure fraction of 50%. (C) 1999 Elsevier Science Irela nd Ltd. All rights reserved.