Magnetic resonance neurography of peripheral nerve tumors and tumorlike conditions.

Peripheral nerve enlargement may be seen in multiple conditions including hereditary or inflammatory neuropathies, sporadic or syndromic peripheral nerve sheath tumors, perineurioma, posttraumatic neuroma, and intraneural ganglion. Malignancies such as neurolymphoma, intraneural metastases, or sarcomas may also affect the peripheral nervous system and result in nerve enlargement. The imaging appearance and differentiating factors become especially relevant in the setting of tumor syndromes such as neurofibromatosis type 1, neurofibromatosis type 2, and schwannomatosis. This article reviews the typical magnetic resonance neurography imaging appearances of neurogenic as well as nonneurogenic neoplasms and tumorlike lesions of peripheral nerves, with emphasis on distinguishing factors.