SCHWANNOMAS

·         Benign tumours

·         Arise from Schwann cells of cranial & spinal nerve roots.

VESTIBULAR SCHWANNOMA

·         a.k.a  ACOUSTIC NEUROMA , NEURILEMMOMA

·         Most common cerebellopontine angle tumour .

·         Most common site of origin- (controversial!) Superior Vestibular Nerve > Inferior Vestibular Nerve > Cochlear Nerve (rare)

·         Most Commonly- Unilateral (95%) & Sporadic

·         Familial forms- usually Bilateral & associated with Neurofibromatosis-2 (NF-2) [ Acoustic neuroma is seldom seen in NF-1 & if present is usually unilateral]

·         Slow growing tumour, with growth in 3 phases:

1.       Internal Auditory Canal

2.       Cisternal phase

3.       Brainstem compression phase

·         Histology- On microscopic examination, tumors show a mixture of two growth patterns

·         Clinical Features:-

§  8^th CN involvement-

1.       Progressive sensorineural Hearing loss (SNHL)

·         Characteristically, speech discrimination is affected more than the pure tone hearing loss.

·         Most common & earliest symptom.

2.       Tinnitus

3.       Dizziness, Vertigo

§  5^th CN involvement-

1.       ↓sensation on one half of the face

2.       Loss of corneal reflex (sign)

§  7^th CN involvement- facial weakness

§  Compression & shifting of the 4^th ventricle causing hydrocephalus & ↑ICT.

·         Diagnosis:-

§  Best Investigation & Investigation of Choice:- Gadolinium Contrast MRI

·         Treatment-

§  Surgical Excision