Acute facial palsy requires urgent medical workup, such as an emergency department or urgent care clinic, to rule out potential life threatening conditions such as a stroke; patients should start appropriate medical therapy as soon as possible.
Facial nerve tumors are relatively uncommon, and the most common among them are called facial nerve schwannomas. These are basically tumors that arise from Schwann cells which are the supporting cells of all nerves, and are found all the way along the course of any nerve in the body. Typically, when somebody has a facial nerve schwannoma, they develop very gradual facial weakness, that is continuously progressive but so slow that one barely notices it unless they compare photographs from month to month or year to year. A typical story might involve somebody noticing that they couldn’t close their eye perfectly one year, and the following year they started looking a little bit different in the mirror when they smiled, etc. Over time, their facial asymmetry becomes noticeable enough that they seek medical attention and if the proper radiology studies are performed, one can identify this tumor. While facial nerve schwannomas are benign, they can cause irreversible facial nerve weakness, and usually require removal when they appear that they might put hearing at risk. In terms of presentation, there are instances where people have very sudden onset facial weakness, which at first glance appears to be Bell’s palsy. However, when they do not experience recovery over the expected time course, further work up is performed that ultimately reveals a schwannoma.
Facial nerve schwannomas do not typically cause weakness that then spontaneously recovers. In order to improve facial function, one will likely require treatment of the tumor either with surgery or radiation therapy, and reconstructing the nerve with a cable graft using a piece of nerve from someplace else in the body. Often this surgical procedure is accompanied by other maneuvers that will also improve facial function. Every case of facial nerve schwannoma is somewhat different, and care is highly individualized to patient age and tumor location, among other considerations.
The other common facial nerve tumor is called a geniculate ganglion hemangioma. This tumor is not a true hemangioma, because the nomenclature has changed quite a bit over the past 30 years. These lesions actually represent vascular malformations that occur in and around the bone at one specific area along the course of the facial nerve, called the geniculate ganglion. These tumors can present with slow onset facial paralysis, much like schwannomas, or they can present with an episode of acute facial paralysis that then recovers, but returns again and again. So if somebody has multiple episodes of facial weakness on a single side, this tumor could be the culprit. Luckily, this tumor is also benign, and we only remove this kind of tumor when it looks like it might cause damage to adjacent structures that could affect hearing, balance, and other important functions, or if we think the best chance for good facial function involves tumor removal. Over the past decade, there has been a great deal of interest in removing geniculate ganglion hemangiomas, while leaving the adjacent attenuated facial nerve in continuity, and this has resulted in significantly improved facial nerve outcomes from prior management, which used to involve resecting everything including the tiny intact strand of facial nerve going through that area.