Lipomas of the internal auditory canal.

Lipomas of the internal auditory canal (IAC) are rare, benign neoplasms occurring in the third to fifth decade of life predominately in Caucasian males. Eleven cases of IAC lesions have been previously reported; we report four more. Two of four cases showed atypical findings on preoperative radiographic evaluation. These two patients had surgery. Two patients with small tumors elected for observation with close follow-up. Fat suppression of T1-weighted images on magnetic resonance imaging (MRI) offers the most precise preoperative diagnostic tool of IAC lipomas. Because of the infiltrative nature of these tumors, hearing conservation surgery is unlikely to succeed. We recommend observation for those patients with small tumors and serviceable hearing.