Acoustic Neuroma & Glomus

Tympanicum

Dr. Vishal Sharma

Acoustic Neuroma

Introduction

A.K.A.: vestibular schwannoma / neurilemmoma

Benign, encapsulated, slow growing tumour

arising from Schwann cells of superior vestibular

division of 8th nerve within internal auditory canal

Rarely from inferior vestibular or cochlear division

Tumor expansion within internal auditory canal

causes widening & erosion of I.A.C.

appears in cerebello-pontine angle (> 2.5 cm)

involves 5th, 7th, 9th, 10th, 11th cranial nerves

displacement of brainstem & cerebellum

raised intracranial pressure

Involvement of 6th & 3rd cranial nerves

Tumour growth

Classification as per size

1. Intra-canalicular: confined to I.A.C.

2. Small: up to 1.5 cm

3. Medium: 1.5 to 4 cm

4. Large: over 4 cm

Tumor size

Intra-canalicular

Small

Medium

Large

Epidemiology 10% of all brain tumors

80% of all Cerebello-pontine angle tumors

Age: 40-60 yrs

Male : Female = 3:2

Unilateral (90%); Bilateral (10%)

Bilateral = von Recklinghausen’s

neurofibromatosis

Clinical Staging

1. Otological stage: due to pressure on 8th nerve

2. Other Cranial nerve involvement

3. Brainstem + Cerebellar involvement

4. Raised intra-cranial tension

5. Terminal stage: failure of vital centers of

brainstem & cerebellar tonsil herniation

Otological symptoms & signs

1. Progressive, unilateral sensorineural deafness

2. Poor speech discrimination (disproportionate)

3. Tinnitus

4. Mild vertigo

5. Nystagmus

Vestibular symptoms appear late due to slow

tumor growth & vestibular compensation

Other Cranial nerve palsy

Trigeminal: first nerve to be involved

Loss of corneal reflex

Pain, numbness and paresthesia of the face

Facial:

Hypoaesthesia of posterior external auditory

canal wall (Hitselberger’s sign)

Facial weakness, Loss of taste, ed lacrimation

Other Cranial nerve palsy

Glossopharyngeal, Vagus & Accessory Spinal:

Dysphagia

Hoarseness

Nasal regurgitation

Decreased gag reflex

Abducent & Oculomotor:

Diplopia

Brainstem involvement

Ataxia Weakness of arms & legs Tendon

reflexes exaggerated

Cerebellar involvement

Ataxic gait (fall on affected side) Intention

tremors Past-pointing Dysdiadochokinesia

Increased Intra-cranial tension

Headache Projectile vomiting Blurred vision

Papillodema Abducent nerve palsy

First Symptoms

Hearing loss: 80-100 %

Vertigo: 10-50 %

Tinnitus: 5-10 %

Ear ache: 5 %

Sudden hearing loss: 5%

Facial paralysis: 1-2 %

Investigations Pure Tone Audiometry: high frequency SNHL

Speech audiometry: SD scores < 30%

Tone decay test: positive

Stapedial Reflex: Decay > 50 % in 10 sec

B.E.R.A.: wave V >4.2 ms; inter-wave V >0.2 ms

Caloric test: I/L canal paresis or no response

C.T. scan with contrast: for tumor > 0.5 cm

M.R.I. with gadolinium contrast: best

Pure Tone Audiogram

Speech Audiometry

Roll over phenomenon

Calorigram

Brainstem Evoked Response Audiometry (B.E.R.A.)

Contrast C.T. Scan

Contrast M.R.I.: neuro-anatomy

Contrast M.R.I. : intra-canalicular

Contrast M.R.I. : small

Contrast M.R.I. : Medium

Contrast M.R.I. : Large

Bilateral tumor: small

Bilateral tumor: large

Treatment1. Observation

2. Microsurgical removal: (partial or total)

Trans-labyrinthine approach

Retro-sigmoid or Sub-occipital approach

Middle Cranial Fossa approach

Combined approach

3. Proton Stereotactic Radiotherapy

4. Brainstem Implant: after B/L tumor excision

ObservationIndications:

1. Age > 60 years with small tumor & no

symptoms

2. Tumour in only hearing / better hearing ear

Serial MRI used to follow growth pattern.

Treatment recommended if hearing is lost or

tumor size becomes life threatening.

House Ear Institute 1977

Incisions

Retro-sigmoid Trans-labyrinthineMiddle cranial fossa

Retro-sigmoid Approach

Sub-occipital approach

Trans-labyrinthine approach

Middle cranial fossa approach

Surgical Approach Protocol1. Intra-canalicular: Middle cranial fossa approach

2. Small (<1.5 cm): Retrosigmoid approach

3. Medium (1.5 - 4 cm)

a. Hearing fine**: Retrosigmoid approach

b. Hearing bad: Trans-labyrinthine approach

4. Large (>4 cm): Trans-labyrinthine / Combined

** Pure Tone Average < 30 dB, S.D. Score >70%

Intra-operative photograph

Proton stereotactic radiotherapySingle high dose of radiation delivered on a

small area to arrest or kill tumor cells. Minimal

injury to surrounding nerves & brain tissue

Gamma Knife: radioactive cobalt

LINAC X-knife: linear accelerator

Cyber-Knife: robotic radio-surgery system

Indication: 1. Surgery refused / contraindicated

2. Post-operative residual tumour

Treatment Planning

Treatment Planning

P.S.R.T. in progress

Pre & Post treatment

Glomus Tumours

Introduction

Synonym: Chemodectoma

Non-chromaffin paraganglioma

Commonest benign tumour of middle ear

derived from glomus bodies distributed along

parasympathetic nerves of head & neck

Consists of paraganglionic cells derived from

embryonic neuroepithelium

Introduction

Histologically benign but locally invasive, highly

vascular, non-encapsulated, slow growing tumors

10 % tumors: familial

10 % tumors: multicentric

10 % tumors: functional (secrete catecholamines)

4 % tumors: metastatic

Histopathology

Typical cellular groups ("Zellballen") surrounded by a capillary network

TypesGlomus jugulare

Arises along jugular bulb & superior vagal

Ganglion, near floor of middle ear

Glomus tympanicum

Arises along tympanic plexus on promontory

formed by tympanic branch of Glossopharyngeal

nerve, near medial wall of middle ear

Spread

Common Symptoms Seen in 40-60 yrs

Female : male = 5:1

U/L deafness: progressive, conductive

Pulsatile tinnitus: synchronous with pulse

decreases on carotid occlusion

Blood stained otorrhoea

Ear ache & vertigo: rare

Signs Rising sun sign: red reflex on otoscopy

Browne’s pulsation sign on siegalization:

Positive pressure tumor engorges tumor

blanches pressure released tumor engorges

Aural mass: bleeds on touch

Systolic bruit: over mastoid on auscultation

Neurological: 9th, 10th 11th cranial nerve palsy

Rising sun sign

Blood-stained otorrhoea

Bleeding polyp

Investigations

1. Pure Tone Audiometry: Conductive deafness

2. High resolution C.T. scan with contrast:

erosion of carotico-jugular spine (Phelp’s sign)

3. Magnetic Resonance Imaging with Gadolinium

contrast: for soft tissue & intra-cranial extension

4. M. R. Angiography: non-invasive. For invasion of

Internal jugular vein & internal carotid compression

Investigations

5. Digital Subtraction Angiography

6. Four Vessel Angiography

Tumour blush

Feeding arteries

Contra lateral circulation

Embolization (within 48 hours of surgery)

Other carotid body tumors

Investigations

7. 24 hour urine Vanillyl Mandelic Acid level:

> 7 mg Catecholamine secreting

tumor Initial hypertension during surgery

followed by hypotension

8. Careful biopsy of mass in ext. auditory canal:

rule out malignancy. Ear packing done for profuse

bleeding.

C.T. scan plain

Glomus Jugulare

Plain & contrast C.T. scan

M.R.I. with contrast

4 Vessel Angiography

Digital Subtraction Angiography

Pre & Post embolization

Magnetic Resonance Angiography

Fisch Staging Stage A: tumor limited to middle ear cleft

Stage B: tympano-mastoid tumor sparing

infra-labyrinthine bone

Stage C: tympano-mastoid tumor eroding

infra-labyrinthine bone

Stage D1: Intra-cranial extension < 2 cm

Stage D2: Intra-cranial extension > 2 cm

Surgical Treatment Anterior Tympanotomy: small stage A

Extended facial recess approach: large stage A

Modified Radical Mastoidectomy: small Stage B

Combined Modified Radical Mastoidectomy +

Fisch’s Infratemporal fossa approach:

large stage B, Stage C

Subtotal temporal bone resection: Stage D1

Anterior Tympanotomy

Infratemporal fossa approach

Facial nerve decompression

Facial nerve re-routing

Tumor excised

Other TreatmentsTele - Radiotherapy (4000 – 5000 rads) or

Stereotactic Radiotherapy:

Inoperable, residual or recurrent tumors;

Pt unfit for surgery or refuses surgery

Observation: Pt > 70 yr with minimal symptoms

Embolization:

Before surgery: reduces vascularity

After RT: for residual or recurrent tumor

Thank You