OBJECTIVETo study the clinical, radiologic and pathologic features of solitary plasmacytoma of spine.

METHODSThe clinical, radiologic and pathologic features, as well as treatment and follow-up data, of 13 solitary plasmacytoma of spine cases were retrieved and analyzed. Immunohistochemical study using EnVision method for LCA, CD19, CD20, CD79a, CD3, CD7, PC, MUM1, CD138, IgG, IgM, kappa, lambda and Ki-67 was carried out.

RESULTSAll the tumours were primarily located in the vertebrae (including 9 cases in thoracic vertebrae and 4 cases in lumbar vertebrae). The male-to-female ratio was 3.3:1. The age of the patients ranged from 42 to 69 years (mean age = 56 years). The commonest symptom was pain in the surrounding regions. The degree of neurologic disturbance mostly depended on the extent of vertebral destruction and structural instability of the spine. Radiologic examination showed mainly osteolytic lesions in vertebrae. Magnetic resonance imaging demonstrated the presence of heterogeneous intensity inside the involved vertebrae (low in T1 weighted and high in T2 weighted images). Histologic examination showed diffuse infiltration by malignant cells. In well-differentiated plasmacytomas, the tumor cells resembled normal plasma cells. In poorly differentiated examples, the cellular morphology mimicked that of the centroblasts. The interstitial stroma was scanty and contained plenty of vessels, sometimes with formation of blood lakes. Amyloid deposition was present in some of the cases. Immunohistochemical study showed that the tumor cells were positive for CD79a and negative for CD20. Light chain restriction was detected in all the 13 cases studied. Plasma cell marker PC was expressed in all cases, while IgG was positive in 5 cases, IgM in 1 case, MUM1 in 10 cases and CD138 in 8 cases. Ki-67 index varied from 10% to 50%. All cases were operated, with adjuvant chemotherapy and radiotherapy given.

CONCLUSIONSCorrelation of clinical, radiologic and pathologic features is important in diagnosis of solitary plasmacytoma of spine. The possibility of multiple myeloma needs to be excluded. Early detection by radiologic examination, local surgical resection, post-operative chemoradiotherapy and long-term follow-up are prudent for successful management of this condition.