A 49-year-old female had experienced headaches and nausea for 2 months. Neurologic examinations showed mild blurring of the optic disc and limitation of ocular movement. Magnetic resonance imaging (MRI) studies disclosed a mass in the central and right paramedian mesencephalon with rostral extension to the third ventricle and the right side of the thalamus. This tumor had a peripheral low signal ring and a heterogeneous central signal on T1 weighted images. The findings were thought to be consistent with a cavernous hemangioma. The clear anatomic boundary of the lesion was defined by MRI enabling removal of the mesencephalic cavernoma. The patient headache remained well xith no neurologic symptoms in the 3 years following the operation.
