Abstract
Schwannomas, optic pathway gliomas (OPGs), and primary central nervous system lymphomas are the three main types of tumors that affect the cranial nerves. Schwannomas are the most common and they affect the vestibular nerve most often. They have characteristic findings on computed tomography (CT) and magnetic resonance imaging (MRI) compared to meningiomas. Gliomas of the cranial nerves are far less common; however, gliomas of the optic nerve/chiasm (OPGs) have a higher incidence and are associated with neurofibromatosis type 1. MRI with gadolinium will demonstrate enhancement of the involved segment of the nerve. Primary central nervous system lymphoma (PCNSL) is typically a disease associated with immunocompromised patients. These tumors rarely involve a single cranial nerve without extension from the parenchyma, though PCNSL of the cranial nerves alone have been reported. This tumor is best imaged using MRI and newer imaging modalities such as MR single-photon-emission CT and [18F]fluorodeoxyglucose positron-emission tomography scans.
