Clinical and pathological characteristics of solitary fibrous tumors

Purpose To assess whether new markers could help to make diagnosis of the solitary fibrous tumor(SFT),and to study its clinical,histopathologic and immunohistochemical characteristics.Methods Tumor tissues from seven cases of SFT were analyzed in this study.Vim,CD34,CD99,bcl-2,Des,SMA,HMBE-1,CK and S-100 protein antibodies were used to detect their expression in the tumors by an immunohistochemical EnVision technique.Results Seven cases of SFT were found in thoracic cavity,abdomen,mediastinum,fossa orbitalis and soft tissue in the chest wall respectively.Majority of the patients demonstrated clinical symptoms due to compression from a large tumor.The size of tumor was ranged from 1.5 cm×1.5 cm×1.0 cm to 20 cm×20 cm×18 cm.Spindle-shaped cells that densely arranged in fascicule and storiform were observed under microscope.Furthermore,a pattern of these tumor cells showing interstitial collagen deposition and a patternless pattern were also found.Immunohistochemically,over-expression of Vim,CD34 and CD99 were observed in all these patients.But only 5 tumors showed bcl-2 positivity.Des,SMA,HMBE-1,CK and S-100 protein were negative.Conclusions SFT is a neoplasm in which variable spindle cells,patternless pattern and collagen deposition can be observed,but it is hard to get a correct diagnosis of the SFT without immunohistochemical analysis.In this study,the high expression of the Vim,CD34 and CD99 in all tumor samples suggests that these markers can be used to identify SFT.However the outcome in patients with SFT depends on factors including tumor size and biological behavior.Surgery is still the first choice for the treatment.If tumor could be removed completely,the patients may have a good prognosis.