RESUMEN
Objective To analyze the clinical,radiological and pathological features of primary leiomyosarcoma of bone and to im-prove the diagnostic level.Methods Totally 6 cases of PLB proved by pathology were collected in our study.The clinical,radiologi-cal and pathological findings were retrospectively analyzed,and combined with the relevant literature to have a comprehensive analy-sis.Results The lesions of 6 patients were solitary,located in femoral (1 case),distal femur (1 case),proximal tibia (2 cases),is-chium (1 case)and humerus (1 case).There was no periosteal reaction in all 6 cases but they all had soft tissue mass,sometimes there may have some mineralization within the tumor.Ill-defined osteolytic bone destruction was detected in 5 patients,while expan-sion of cystic bone destruction was found in the other 1 patients.3 cases had hardened edge,2 cases with adjacent bone cortical thickening.The MR imaging in 5 patients showed iso-intensity signal on T1 WI,a slightly inhomogeneously higher signal on T2 WI and a significant heterogeneously enhancement after injected of Gd-DTPA.Another 1 patient showed a double ring sign,the central area onT1 WI and T2 WI expressed heterogeneous slightly higher signal,the peripheral annular zone was iso-intensity on T1 WI and slightly higher on T2 WI,after injected contrast medium,it was inhomogeneous enhancement.In immunohistochemically,all tumors reacted positively with SMA,3 patients with Desmin and Vimentin positive,2 patients with Ki-67 positive,and there had some scat-tered cells with CD68 positive,but the S-100 were all negative.Conclusion The clinical,radiological and conventional histological manifestations of PLB are not specific.Immunohistochemical and/or ultrastructural analysis who displayed smooth muscle differenti-ation can confirm the diagnosis.