Analyses of prognosis-related factors of intracranial solitary fibrous tumors and hemangiopericytomas help understand the relationship between the two sorts of tumors.

Increasing evidence has suggested a close relationship between solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) in the central nervous system (CNS). However, CNS SFTs differentiate from HPCs in their clinical behavior and patient prognoses. Analyses of prognosis-related factors can help clarify the relationship between SFT and HPC. The intracranial SFT and HPC cases treated in our departments from January 2002 to December 2012 were retrospectively reviewed. The SFT and HPC cases were also combined into an SFT/HPC group. The factors associated with patient progression-free survival (PFS) and overall survival (OS) were statistically analyzed using uni- and multivariate analyses. Fifty-eight intracranial SFT/HPC patients including 38 SFT patients and 20 HPC patients were treated during this period. The "Marseille grading" evaluated upon the histological aggressive phenotypes was applied in this study. The grading reflected a malignant progression ranging from "conventional" SFTs (grade I) to WHO III HPCs (grade III), and grade was negatively correlated with the PFS and OS of the SFT, HPC and SFT/HPC patients (P < 0.05).The multivariate analyses revealed that gross total resection (GTR) was significantly positively correlated with PFS and OS in the SFT, HPC and SFT/HPC patients and that radiotherapy was significantly positively correlated with PFS in the HPC and SFT/HPC patients (P < 0.05). In conclusion, the intracranial SFTs and HPCs share common prognostic factors including extent of surgery and pathology, moreover, the histological grading of the aggressive phenotypes supports the unifying of the CNS SFT and HPC into one tumor entity of SFT/HPC.