Hypervascular vestibular schwannoma: A case report and review of the literature.

Vestibular schwannomas, also known as acoustic neuromas, are benign tumors that arise from Schwann cells near the transition from glial cells to Schwann cells. While most vestibular schwannomas are hypovascular tumors, a small percentage constitute the hemorrhagic and/or hypervascular vestibular schwannomas (HVS) subtype. We describe a case of a 36-year-old female who presented with nausea, vomiting, and an acute decrease in vision in her right eye. Computed tomography of the head demonstrated a hemorrhagic lesion in the right hemisphere with evidence of ventricular effacement. Follow-up magnetic resonance imaging revealed a mass in the right cerebellopontine angle that was hypointense on T1-weighted imaging and mild hyperintense heterogeneous signal on T2-weighted imaging, suggestive of a hemorrhagic vestibular schwannoma. It is important for radiologists to recognize the unique clinical and radiological features of HVS in the initial diagnostic assessment of cerebellopontine angle tumors and to distinguish it from common (hypovascular) vestibular schwannomas and other related pathologies. A preoperative diagnosis of HVS allows clinicians to become familiar with the unique characteristics of the tumor and to devise a feasible operative strategy prior to surgical resection.