Grade III solitary fibrous tumor/hemangiopericytoma: An enthralling intracranial tumor-A case report and literature review.

Hemangiopericytomas account for less than 1% of all intracranial tumors. In 2016, World Health Organization (WHO) unified the two terms into a single medical condition known as solitary fibrous tumor/hemangiopericytoma (SFT/HPC). Our patient is an 80-year-old woman with a past medical history of sick sinus syndrome status post pacemaker placement. She presented to the emergency department with progressive headaches for one month duration. Her headaches worsened at night, waking her up from sleep. They also increased in intensity by bending forward. Review of systems was significant for bilateral lower extremity weakness accompanied by difficulty walking. The motor exam was remarkable for right upper and right lower extremity 3/5 weakness. The gait was ataxic. A Computed tomography scan of the head without contrast revealed a large dural-based right parietal hyperdense mass with surrounding edema, mass effect, and compression of the right lateral ventricle atrium. A right-to-left midline shift was also noted. Given the fact that our patient had a pacemaker, she was not a candidate for a brain MRI. Neurosurgery successfully resected the mass. Histopathological studies confirmed WHO grade III anaplastic solitary fibrous tumor/hemangiopericytoma. The patient was discharged on adjuvant radiation with imaging surveillance given the grade and the extent of resection. This case highlights a rare type of intracranial mass that resembles meningioma on imaging studies. It also illustrates that solitary fibrous tumor/hemangiopericytoma should be kept as a differential diagnosis for brain masses, given its aggressive nature, and its potential of metastasis and recurrence.