Solitary fibrous tumor of vulva:a clinicopathologic analysis of a case and review of literature

Purpose To explore the clinical pathological features,immunohistochemical characteristics and differential diagnosis of solitary fibrous tumor(SFT) of the vulva.Methods A case of SFT of the vulva was examined with light microscopy and immunohistochemistry,including CD34,bcl-2,CD99,vimentin,CK(AE1/AE3),HMB-45,α-SMA,CD117,S-100 protein,ER,PR and Ki-67 with EnVision method,and related literatures were reviewed.Results The patient was a 62-year-old woman.Clinical and radiological examination revealed a tumor in the vulva for 4 years.Grossly,the tumor was nodular with dimension 6 cm×5 cm×3 cm,well-circumscribed with grey white color on cut surface.Microscopically,the tumor was composed of bland spindle-shaped cells and dense collagenous bands,with fascicular,storiform,or haphazard arrangements.Focal areas showed a haemangiopericytoma-like structure.Immunohistochemically,the tumor cells were positive for CD34,bcl-2,CD99 and vimentin,but negative for CK(AE1/AE3),HMB45,α-SMA,CD117,S-100 protein,ER and PR.Ki-67 index was less than 1%.Conclusions SFT is a very rare tumor,especially in vulva,and it should be differentiated from the tumors that have features similar to hemangio-perithelioma.