Solitary Fibrous Tumor/Hemangiopericytoma Mimicking a Trigeminal Schwannoma: Case Report and Review of the Literature

Background Solitary fibrous tumor (SFT)/hemangiopericytomas make up less than 1% of primary central nervous system tumors. The purpose of this report is to describe the clinical presentation of an SFT/hemangiopericytoma arising from Meckel’s cave.

Case Report A 40-year-old man presented to the neurosurgery clinic at an academic, tertiary hospital with right facial numbness, a 3-month duration of worsening coordination, and occasional diplopia. On physical examination, he was alert and oriented with clear and fluent speech. Cranial nerves were intact except for right facial hypesthesia. His gait was wide-based slightly ataxic. T1-weighted MRI without contrast demonstrated an isodense, bilobed lesion located in the right Meckel’s cave and cerebellopontine angle. This lesion enhanced after contrast administration and was heterogeneously bright on T2-weighted MRI. Given these findings, the lesion was favored to be a trigeminal schwannoma. The patient was electively scheduled for a right frontotemporal craniotomy with anterior petrosectomy for tumor biopsy and likely resection. However, shortly after his clinic visit, the patient reported an acute decline in balance, dense right facial numbness in V1 to V3 distribution, slightly slurred speech, and ataxia. A repeat MRI demonstrated mild hydrocephalus without significant tumor enlargement. The patient was admitted for concern of brainstem compression and taken to the OR prior to the scheduled date.

Results Intraoperatively, soft tumor was noted to intimately involve the right trigeminal nerve. There was invasion into the right cavernous sinus/Meckel’s cave and posterior fossa regions. Frozen section returned as a small blue cell tumor and final pathology revealed a WHO Grade III SFT/hemangiopericytoma. A subtotal resection was achieved. Following surgery, the patient’s balance and coordination improved, but his facial hypesthesia remained. His hearing and facial nerve function were intact. He underwent adjuvant radiation.

Discussion Intracranial SFT/hemangiopericytomas carry a high rate of recurrence and risk of extracranial metastases. Reports of SFT/hemangiopericytomas arising from Meckel’s cave and the cerebellopontine angle have rarely been described. The unusual progression of symptoms in the setting of a benign radiographic appearance highlights the need to consider this etiology for appropriate management.

Conclusion Intracranial SFT/hemangiopericytomas are rare and may mimic benign etiologies on radiographic studies. This report highlights the need to consider SFT/hemangiopericytoma in the differential diagnosis for appropriate management.