Abstract: Objective :To explore the nature and relationship between solitary fibrous tumor (SFT)and hemangiopericytoma (HPC) by morphologic and immunohistochemical observation. Methods :Twelve cases of SFT and 6 cases of HPC were analyzed by clinicopathologic study and immunohisto-chemical staining of CD34, CD99 and Bcl-2. Results :Histologically, SFT was composed of numerousspindle cells with variable cellularity, local hemangiopericytoma- like areas,scattered dense collage-nization and perivascular hyalinization. HPC showed a monomorphic population with a branching "staghorn" vascular pattern. SFT exhibited diffuse positive for CD34 (100%), Bcl-2 (100%), and CD99(75.00%).HPC was positive for CD99 and Bcl-2 (both 66.67%), but only 16.67% for CD34. Conclu-Sion :Both SFT and HPC belong to the fibroblastic and myofibroblastic neoplasm category with histo-logic and immunohistochemical overlap, but the morphologic differences allow us to infer the 2 lesionsconstitute distinct entities.