Synonyms:
formerly localized hypertrophic mononeuropathy
Diagnosis:
Suggested by MRI and confirmed by pathology (brain biopsy/resection)
Findings on Investigations:
MRI:
- MRI neurography (fat saturated T2 or fat saturated T1 post Gadolinium):
- Hypertrophic nerve, fusiform, several 5-10cm or more.
- Upper limb: posterior interosseus, radial, ulnar nerves. Or lower limb: sciatic, peroneal, tibial, femoral nerves
Pathology:
Histology:
- HE: thickened perineurium, Endoneurial “Pseudoonion bulbs”= Whorles of perineurial cells
Immunohistochemistry: EMA positive, S100 negative