Trigeminal neurinoma presenting as intratumoral hemorrhage--case report.

Neurinomas of trigeminal nerve are rare intracranial tumors and spontaneous intratumoral hemorrhage occurred exceedingly rarely in them. Herein, we report one case of trigeminal neurinoma presenting spontaneous intratumoral hemorrhage. Presenting symptoms were headache, lethargy and vomiting of sudden onset. Unenhanced computed tomography scans showed a high density mass in the left cerebellopontine angle cistern. On magnetic resonance images, they revealed hyperintensity on both T1- and T2-weighted images. A left retromastoid suboccipital craniectomy was performed and nearly total tumor removal was achieved. Histologically, increased vascularity, dilated vessels and hemosiderin were observed in the specimen. Tumor size, hypervascularity and vascular change are important factors for hemorrhage.