Hypoglossal nerve schwannoma with intratumoral hemorrhage.

Intratumoral hemorrhage of hypoglossal schwannoma is very rare. A 37-year-old man was admitted to our hospital with severe headache and gait disturbance. Radiologic examination revealed subarachnoid hemorrhage and a well-circumscribed enhanced lesion compressing the medulla oblongata. Gross total removal of the intracranial tumor was performed. Histopathological examination revealed the characteristic features of a schwannoma. The tumor had several hemorrhagic areas and numerous hyalinized blood vessels. Although the mechanism of hemorrhage from schwannomas is unclear, it is hypothesized that tumor vessels showing focal sinusoidal dilatation and hyaline thickening of the walls lead to spontaneous thrombosis with consequent necrosis, and often hemorrhage.