The almost-invisible perineurioma.
Intraneural perineurioma is a rare, benign slow-growing lesion arising from the perineurial cells that surrounds the peripheral nerve fibers. Typically it presents during childhood and young adulthood as a motor mononeuropathy. MRI plays an essential role in the diagnosis and localization of the lesion, which appears as a fusiform enlargement of the nerve fascicles that enhances intensely with gadolinium. Despite the typical clinical and radiological features, intraneural perineurioma remains largely underdiagnosed because of the lack of familiarity with this entity, but also as a result of technical limitations with conventional MRI that is typically performed as a screening test over a large field of view and without contrast sequences. The purpose of this article is to present the pitfalls and pearls learned from years of experience in the diagnosis and management of this relatively rare condition. Clinical suspicion and detailed neurological examination followed by high-quality electrophysiological studies (EPS) must lead to an adequate preimaging localization of the lesion and narrowing of the imaging area. The use of high-resolution (3-T) MRI combined with gadolinium administration will allow adequate visualization of the internal anatomy of the nerve and help in differentiating other causes of neuropathy. In cases where the lesion is not recognized but clinical suspicion is high, possible errors must be assessed, including the EPS localization, area of imaging, MRI resolution, and slice thickness.
Departments of 1 Neurologic Surgery.
Carlos E
CE
Restrepo
Radiology, Mayo Clinic, Rochester, Minnesota.
Kimberly K
KK
Amrami
Radiology, Mayo Clinic, Rochester, Minnesota.
Benjamin M
BM
Howe
Neurology, and.
P James B
PJ
Dyck
Neurology, and.
Michelle L
ML
Mauermann
Departments of 1 Neurologic Surgery.
Robert J
RJ
Spinner
D002648:Child; D019468:Disease Management; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D005682:Gadolinium / Q000378:metabolism; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis*; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis*
D005682:Gadolinium
3 Tesla; CIDP = chronic inflammatory demyelinating polyneuropathy; CMT = Charcot-Marie-Tooth disease; EMA = endothelial membrane antigen; EPS = electrophysiological studies; GBS = Guillain-Barré syndrome; PNST = peripheral nerve sheath tumor; SPGR = spoiled gradient; intraneural perineurioma; magnetic resonance imaging; targeted biopsy