Vestibular Schwannoma a.k.a. acoustic neuroma (formerly neurilemmoma)
Suggested by MRI and confirmed by pathology (brain biopsy/resection)
- Antoni A pattern: cellular, Spindle cells. Verocay bodies (palisading).
- Antoni B pattern: less cellular, round nuclei, vacuolated cells, microcysts
Immunohistochemsitry: Positive S100
Findings on Investigations:
- VIII nerve. Extends into the internal auditory canal IAC. May affect cranial nerves VII, V or any other. Cisternal & intracanalicular portions. Cysts may occur. No calcifications, no bony reaction, no dural tail.
- May occur in spinal nerve roots. Hourglass/Dumbbell shaped mass through the intervetrebal foramen
- T1 MRI with gadolinium: isointense to hypointense. Enhancement
- T2: variable signal intensity
- Fat saturated MRI: distinguishes fat.
- Associated with arachnoid cyst
Audiological testing: may be impaired
- Electronystagmography ENG