Optic nerve choristoma.

Choristomas are rare lesions that typically involve peripheral nerves and are marked by the presence of histologically normal tissue for an organ or body part other than the site at which it is located. Reports of choristoma involving cranial nerves are extraordinarily rare. We report a case of an optic nerve choristoma arising in a 24-year-old woman. The lesion was marked by a disordered admixture of smooth muscle tissue and optic nerve tissue. The literature on optic nerve choristoma is reviewed.