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2. Objectives
 Acoustic Neuroma:
definition,
histopathology
 Etiopathogenesis
 Classification
 Clinical Features
 Management
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3. FAQ’s in RGUHS
• Acoustic Neuroma
• Clinical features of acoustic neuroma
• Hitzelberger’s sign

4. Acoustic Neuroma
• Definition:
Tumour of eighth cranial Nerve.
• Eponyms:
Vestibular Schwannoma
Neurilemmoma
• Incidence:
80% of Cerebellopontine angle tumours
10% of all brain tumours

5. Pathology
• Gross:
Benign, Encapsulated,
Slow-growing
• Microscopy:
Elongated spindle cells
Rod-shaped nuclei in rows
or palisades.

6. Origin & Growth
• Origin:
Schwann Cells of Vestibular Nerve, rarely from
cochlear nerve
• Growth: (slow)
 Causes widening and erosion of the canal and
appears in the CP angle
 Anterosuperior growth: 5th
 Inferior: 9th , 10th & 11th
 Later stages: displacement of brainstem, pressure on
cerebellum and raised intracranial tension

7. Origin & Growth

8. Classification
Acoustic
Neuroma
Intracellular
Small Size
<1.5cm
Medium size
1.5-4cm
Large Size
> 4cm

9. Clinical Features
• Age : 40-60 years
• Sex: M=F
• Symptoms:
1. Progressive unilateral SNHL
2. Tinnitus
3. Marked difficulty in understanding speech
4. Imbalance/ Unsteadiness
5. Vertigo
6. Sudden Hearing loss
7. Fullness in the ear

10. Cranial Nerve Involvement
1. 5th nerve: EARLIEST
Reduced cornea sensitivity, paraesthesia of face
Involvement indicates : tumour size = 2.5cm &
occupies CP angle
2. 9th & 10th : dysphagia & hoarseness due to
palatal, pharyngeal, laryngeal paralysis
3. Other cranial nerves: affected only when tumour
size is very large

11. Cranial Nerve Involvement
Facial nerve:
• Sensory fibres are affected early.
• Hitzelberger’s sign : Hypoaesthesia of
posterior meatal wall
• Loss of taste ( Electrogustometry)
• Schirmer test : Reduced lacrimation
• Motor fibres: Affected late
• Delayed blink reflex

12. Brainstem Involvement
• Ataxia
• Weakness & Numbness of arms
and legs
• Exaggerated tendon reflexes
Raised Intra-cranial tension
Headache, nausea, vomiting, diplopia(6th) &
papillo-edema with blurring of vision.

13. Cerebellar involvement
• Pressure symptoms on cerebellum are seen in
large tumors
• Revealed by
 Finger-nose test
 Knee-heel test
 Dysdiadochokinesia
 Ataxic gait
 Inability to walk along a straight line (tendency to
fall on the affected side)

14. Investigations
• Audiological tests:
1. PTA
2. Speech Audiometry
3. Recruitment
phenomena: Absent
4. Short Increment
Sensitivity Index: 0-20%
5. Threshold tone decay
test : Retrocochlear type
of lesion

15. Vestibular Tests
• Caloric test:
Diminished or absent
response in 96% of
patients
May be normal when
tumour is small

16. Neurological Tests
Complete examination of:
• Cranial nerves
• Cerebellar functions
• Brainstem signs of pyramidal & sensory tracts
• Fundus

17. Radiological tests
1. Plain X-ray:
• Positive in 80% of patients
• Different views:
1. Transorbital
2. Stenver’s
3. Towne’s
4. Submentovertical
2. Vertebral angiography:
• Helps in differentiating AN from other tumours

18. Radiological Test
3. CT scan:
• More sensitive than X-ray
• Can detect even intra-meatal and
posterior fossa tumors
4. MRI with Gadolinium contrast:
• GOLD Standard
• Can detect even intracanalicular
tumours of few mm

19. Stapedial reflex Decay Test

20. Other tests
• BERA:
A delay of >0.2ms in
wave V between 2 ears in
case of 8th nerve tumour
• CSF Examination:
Protie level raised, Lumbar
puncture should be
avoided

21. Investigations
Important tests for AN work-up:
• PTA
• Speech discrimination score
• Roll-over curve
• Stapedial reflex decay
• BERA
• MRI with gadolinium contrast

22. Differential Diagnosis
• Meniere’s Disease
• Tumours of CPangle:
1. Meningioma
2. Epidermoid
3. Arachnoid Cyst
4. Schwannoma of other cranial nerves
5. Aneurysm
6. Glomus tumour
7. Metastasis

23. Treatment
Treatment
Surgical Radiotherapy

24. Surgical
• Treatment of Choice
Approaches
Middle Cranial
Fossa
Translabyrinthine Suboccipital
Combined
translabyrinthine-
suboccipital

25. Radiotherapy
1. Conventional Radiotherapy
2. X-knife/ɣ-knife surgery
3. Cyber knife

26. X-knife/ɣ-knife surgery
• Stereotactic radiotherapy
• Advantages:
1. Minimal radiological effect
2. Causes reduction in tumour size &
growth.
3. Can be used in patients where surgery is
not feasible.
• Procedure : linear accelerator
ɣ-knife through cobalt-60

27. Radiotherapy
Conventional:
• Not prefered now due to low
tolerance of CNS to radiation
Cyber knife:
• Modified X-knife
• More accurate & frameless
• Method: real-time image
guidance technology through
computer controlled robotics.