The case of a 48 year-old woman present ng with a primary pontine hematoma is reported. The clinical evolution simulated a brain stem tumor and the diagnosis of hematoma was not established before the operation. The preoperative neurological deficit improved except for a facial nerve palsy. These hematomas are thought to be due to rupture of «cryptic» arteriovenous malformations and should be differentiated from those secondary to systemic hypertension. The diagnosis of brain stein hematomas should be considered in any case of brain stem lesion, especially in young and normotensive patients.