Facial nerve choristomas are rare, being characterised by non-neoplastic proliferation of smooth muscle cells and fibrous tissue. Facial nerve choristomas presumably can occur anywhere along the course of the facial nerve (CN VII), although the only cases reported are in the internal acoustic meatus and in the region of the geniculate ganglion.
This is with a lower motor neurone facial palsy. However, choristomas have also been reported affecting other cranial nerves as well as the eye.
They are indistinguishable from acoustic schwannomas on imaging, appearing as small circumscribed enhancing soft tissue nodules on contrast enhanced MRI, which is the imaging modality of choice.
Treatment and prognosis
Complete surgical resection is curative and no adjuvant therapy is required. However, there can be morbidity related to the the surgery including facial nerve palsy and hearing loss due to intra-operative nerve injury.
- 1. MM Smith et al "Choristomas of the Seventh and Eighth Cranial Nerves" AJNR:18,February1997