Lipomas of the middle ear and posterior fossa

Lipomas of the intracranial cavity and the middle ear are rare tumors. There have been only 4 cases of lipomas of the middle ear described in the English literature. A small subset of intracranial lipomas occurs within the internal auditory canal and the cerebellopontine angle. In this location, these tumors account for 9% of intracranial lipomas. Historically, removal of these tumors is difficult due to adherence to adjacent cranial nerves, brainstem, and incorporation of vessels and nerve fascicles within the tumor. This has led to a high rate of postoperative neurologic deficits and incomplete resection. In a recent review of all posterior fossa lipomas to date, only 33% of lipomas could be completely resected. With complete tumor resection hearing was preserved in 12%. Hearing was preserved in 23% of CPA lipomas with partial resections. Review of hearing preservation rates reported for complete removal of tumors limited to the IAC is 40%. We present 3 cases: a cerebellopontine angle lipoma, a lipoma of the internal auditory canal, and a middle ear lipoma. Interestingly, we observed no change in audiometric thresholds after a middle fossa resection of the internal auditory canal lipoma. Specifically looking at small lipomas limited to the internal auditory canal, this case illustrates hearing preservation may be possible.