Intracranial Lipomas Affecting the Cerebellopontine Angle and Internal Auditory Canal: A Case Series and Literature Review

Objective: To assess the long-term outcome of lipomas affecting the cerebellopontine angle (CPA) and internal auditory canal (IAC).

Design: This is a retrospective, single-center study of ten CPA and IAC lipomas that have presented over the last 6 years. The natural progression, audiovestibular signs and symptoms, imaging characteristics, and management options have been evaluated.

Results: There were six lesions within the IAC only, two confined to the CPA and two involving both sites. The average size was 8 mm. All patients presented with hearing loss and a majority had tinnitus, although only two had imbalance or vertigo. One patient required operative intervention for incapacitating vertigo. The other nine were managed conservatively. Follow-up imaging was available for seven of the cases and no growth was observed in any of these, with an average follow-up of 3.5 years.

Conclusion: Most reports in the literature of these rare lesions are in the form of case studies. Due to the resolution of modern imaging, lipomas of the IAC and CPA are increasingly being recognized and accurately diagnosed. Our data suggest that these lesions are more common than previously thought, representing approximately 1% of all lesions in this location referred to our center. Based on the absence of growth in the majority of cases, with follow-up averaging of 3.5 years, we recommend that these lesions be managed conservatively by serial imaging. In rare cases, surgery may be required if the lesion is resulting in incapacitating symptoms such as significant balance disturbance.