Angiographic diagnosis of intra- and extraaxial tumors in the cerebellopontine angle.

Angiography is an effective diagnostic modality in the evaluation of patients with suspected cerebellopontine angle tumor, particularly when there is not a clear clinical differentiation between an intraaxial and an extraaxial mass, or when the patient presents with increased intracranial pressure. In a series of 17 extraaxial masses in the cerebellopontine angle and 2 cerebellar tumors which presented into the angle, the most common angiographic findings were: 1. elevation and/or medial displacement of the proximal portions of the superior cerebellar artery; this finding was seen only in the extraaxial tumors and has not been demonstrated with intraaxial masses; 2. downward, medial, and posterior displacement of the proximal portions of the posterior inferior cerebellar artery; 3. lateral displacement and stretching of the hemispheric branches of both the superior cerebellar and posterior inferior cerebellar arteries; and 4. displacement of the vein of the lateral recess and of the petrosal vein either downward and medially or upward and laterally.