Intracranial Solitary Fibrous Tumor/Hemangiopericytoma: A Clinicoradiological Poorly Recognized Entity- An Institutional Experience.

Abstract

Intracranial solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) are rare nonmeningothelial mesenchymal tumors sharing fusion of NGF1-A binding protein 2 (NAB2) and signal transducers and activators of transcription (STAT6.).The WHO classification of central nervous system (CNS) tumors (2016) highlights that molecular confirmation of NAB2/STAT6 fusion or immunohistochemical nuclear expression of STAT6 is mandatory for the diagnosis of SFT/HPC.Herein, we present a series of four cases of SFT/HPC of the brain, which mimicked other CNS tumors both clinically and radiologically. This is a retrospective study over a period of two and a half years. Out of the 156 operated cases of brain tumors, four patients (2.56%) were diagnosed with SFT/HPC. The clinicoradiological details with the surgical procedure were retrieved from the archived hospital records. All cases were males, of which three were in their 5th decade while one was a 14-month-old baby. Two cases were primary and the rest were recurrent.The location of tumors was extra-axial left cerebellotentorial,clivaldural-based,left cerebellar, and in the left frontoparietal region,respectively. The clinical impression was meningioma in three cases,while it was primitive neuroectodermal tumor (PNET) /atypical teratoid/rhabdoid tumor (ATRT) in one case.With the detailed histomorphology and immunohistochemistry, the final diagnosis was anaplastic hemangiopericytoma(WHO grade III) for all the cases. During our follow-up, one patient died with the disease, while the rest are doing well. SFT/HPC should be kept in the differential diagnosis of all dura-based hypervascular masses, especially in recurrent cases, due to its aggressiveness and high recurrence rate.