Magnetic resonance imaging and trigeminal schwannoma.

A case of trigeminal schwannoma, extending from the posterior fossa into Meckel's cave, is reported. The information provided by computed tomography, angiography, and magnetic resonance imaging allowed a correct preoperative diagnosis to be obtained. Due to the excellent sensitivity, the absence of bone artifacts, and the ease of imaging in any plane, magnetic resonance imaging best defined the "dumbbell" nature of the tumor, the atrophy of the masticatory muscles, and the infiltration of the third division of the trigeminal nerve.