For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant, degenerating into a form of cancer known as neurofibrosarcoma.

[3] Schwannomas can be associated with neurofibromatosis type II, which may be due to a loss-of-function mutation in the protein merlin.

Schwannomas of the head and neck are a fairly common occurrence and can be found incidentally in 3–4% of patients at autopsy.

[4] Most common of these is a vestibular schwannoma, a tumor of the vestibulocochlear nerve that may lead to tinnitus and hearing loss on the affected side.

Outside the cranial nerves, schwannomas may present on the flexor surfaces of the limbs.