Abstract: Objective:To investigate the clinical features, treatment strategies, and relative prognostic factors in 66 patients with solitary plasmacytoma (SP). Methods: The data of 644 patients, who were diagnosed with pathologically proven plasmacytoma in Tianjin Medical University Cancer Institute and Hospital between June 2000 and October 2012 , were collected. Sixty-six of these patients ( 10 .25 %) were evaluated as SP, including 45 solitary bone plasmacytoma (SBP) and 21 extramedullary plasmacytoma (EMP). Results:SBP and EMP were the two clinical subsets of SP revealing the location of the lesion. SBP mostly occurred in the axial skeleton, whereas EMP was most frequently observed in the upper respiratory tract. The differences among tumor size, serum M-protein, and serumβ 2-microglobulin exhibited statistical significance.Conclusion:Large tumor size (≥5 cm), positive serum M-protein, and serum β 2-microglobulin were the factors that affected the prognosis of SBP patients. Radiotherapy and serum β 2-microglobulin > 3.5 mg/L were the favorable prognostic factors for EMP patients.