Clinical study and differential diagnosis of intracranial hemangiopericytomas

Objective Intracranial hemangiopericytomas (HPCs) were rare neoplasms with relatively high rates of recurrence and extracranial metastasis. The differential diagnoses from angiomatous meningiomas and solitary fibrous tumors(SFTs) are very important. This study is aimed to reveal differences in the specific immunohistochemical features of HPCs, angiomatous meningiomas and SFTs by newly developed immunohistochemical methods. Method Eleven sequential cases of HPC diagnosed in Renji hospital between 1993 and 2010 were retrospectively analyzed by immunohistochemical staining for CD34,Bcl -2 and epithelial membrane antigen ( EMA ). The cases were then re - evaluated and newly diagnosed based on the results of the immunohistochemical stainings. Results One of the eleven cases was newly diagnosed as SFTs and nine were reconfirmed as HPCs, based on the immunohistochemical studies for CD34,Bcl - 2 and EMA staining. One case was newly diagnosed as angiomatous meningioma on the basis of a strong EMA staining positivity. Three HPCs recurred and one HPC patient died of the tumor. Conclusions Given that SFTs and angiomatous meningioma have a considerably better prognosis than HPCs, it is important to carry out meticulous immunohistochemical examinations for primary diagnosis. Key words: Hemangiopericytoma; Solitary fibrous tumor; Angiomatous meningioma