Hemifacial spasm associated with epidermoid tumors of the cerebellopontine angle.

Hemifacial spasm (HFS) is rarely due to serious compressive lesions, such as tumors, aneurysms, or vascular malformations, located in the cerebellopontine angle. Because of the interesting association of HFS with epidermoid tumors, we reviewed the records of all patients with HFS and all patients with intracranial epidermoid tumors seen from January 1975 to December 1986. Of the 18 patients who had epidermoid tumors of the cerebellopontine angle, 3 (17%) had a facial movement disorder that resembled HFS at sometime during their illness. There were 429 patients who had HFS with no obvious serious compressive lesion of the facial nerve. Therefore, HFS was associated with epidermoid tumor in 0.7% of cases. All 3 patients developed other findings due to involvement of adjacent neural structures. Patients with HFS have a low probability of having a serious compressive lesion, but those with atypical features should be evaluated for cerebellopontine angle masses such as epidermoid tumors.