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: elevation and/or medial displacement of the proximal portions of the superior cerebellar artery; this findings was seen only in the extraaxial tumor and has not been demonstrated with intraaxial masses; downward, medial, and posterior displacement of the proximal portions of the posterior inferior cerebellar artery; lateral displacement and stretching of the hemispheric branches of both the superior cerebellar and posterior inferior cerebellar arteries; and displacement of the vein of the lateral recess and of the petrosal vein either downward and medially or upward and laterally.