Objective:The aim of this study was to investigate the clinicopathologic characteristics,diagnosis and differential diagnosis,molecular genetics,treatment and prognosis of solitary fibrous tumor(SFT).Methods:The clinicopathological manifestations were analyzed retrospectively in 22 patients with surgically confirmed SFT.Results:There were 12 male patients and 10 female patients,with the age range 33-67(mean 48.62) years.The SFTs originated from different from parts of the body,including 13 in the chest,2 in the lungs,3 in the abdomen,1 in the lumbosacral area,2 in the pelvis,and 1 in the left shoulder.There were 19 benign and 3 malignant tumors.Major clinical presentations were local masses and compression symptoms.Microscopy:the tumor was composed of areas of alternating hypercellularity and hypocellularity.The tumor cells were spindle to short-spindle shaped and arranged in fascicular or storiform pattern and hemangiopericytoma-like structure was presented.Immunohistochemically,Vimentin positive rate was 100%(22/22),Bcl-2 positive rate was 95.5%(21/22),CD99 positive rate was 86.4%(19/22),CD34 positive rate was 81.8(18/22),focally positive for P53,as well as negative CK,S100 and Desmin.Ki67 labelling index was 2%-30%.Conclusion:SFT is a rare tumor which may be found in various parts of human body.SFT mostly is a benign tumor,but a few could be malignant.Its diagnosis mainly rely on its morphologic features and immunohistochemical profiles.The major treatment is to completely resect it by operation and long-term clinical follow-up is necessary. Objective: The aim of The study was to investigate the clinicopathologic characteristics, diagnosis and differential diagnosis, molecular genetics, treatment and prognosis of solitary fibrous tumor (SFT). Methods: The clinicopathological manifestations were analyzed retrospectively in 22 patients with surgically confirmed SFT. Results : There were 12 male patients and 10 female patients, with the age range 33-67 (mean 48.62) years.The SFTs originated from different from parts of the body, including 13 in the chest, 2 in the lungs, 3 in the abdomen , 1 in the lumbosacral area, 2 in the pelvis, and 1 in the left shoulder. There were 19 benign and 3 malignant tumors. Major clinical presentations were local masses and compression symptoms. Microscopy: the tumor was composed of areas of alternating hypercellularity and hypocellularity. The tumor cells were spindle to short-spine shaped and arranged in fascicular or storiform pattern and hemangiopericytoma-like structure was presented. Immunohistochemically, Vimen positive rate was 100% (22/22), positive rate of Bcl-2 was 95.5% (21/22), positive rate of CD99 was 86.4% (19/22), positive rate of CD34 was 81.8 (18/22), focally positive for P53, as well as negative CK, S100 and Desmin. Ki67 labelling index was 2% -30%. Confusion: SFT is a rare tumor which may be found in various parts of human body. SFT mostly is a benign tumor, but a few could be malignant.Its diagnosis mainly rely on its morphologic features and immunohistochemical profiless.The major treatment is to completely resect it by operation and long-term clinical follow-up is necessary.