A clinicopathological and immunohistochemical study of central nervous system hemangiopericytomas.

Hemangiopericytomas (HPC) of the central nervous system (CNS) are uncommon dural-based tumors that mimic meningiomas clinically and radiologically. Because there are few reports about these tumors from India, we aimed to study the clinico-pathological and immunohistochemical features of CNS HPC. During 2000 to 2008 all 23 patients diagnosed with HPC of CNS at our Institution were reviewed in the study (11 males and 12 females, mean age of 46 years). Clinical, radiological and histopathological features were reviewed. There were 14 patients with grade II and nine with grade III tumors. Immunohistochemistry with antibodies to epithelial membrane antigen (EMA), vimentin, S-100, CD34 and Ki-67 was done on routinely processed, paraffin-embedded sections of 20 tumors. All patients were EMA and S-100 negative, and vimentin positive. CD34 was positive in only five out of 20 patients. The mean Ki-67 labeling index was 4.25% in grade II tumors and 7.8% in grade III tumors. We concluded that HPC are distinct from meningiomas in morphology, immunohistochemistry and biologic behavior, although they resemble each other clinically and radiologically, HPCs need to be differentiated from meningiomas.