Download Acoustic Neuroma & Glomus Tympanicum

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
Tumour growth
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
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
Treatment
1. 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
Observation
Indications:
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
Middle cranial fossa
Retro-sigmoid
Trans-labyrinthine
Retro-sigmoid Approach
Sub-occipital approach
Trans-labyrinthine approach
Middle cranial fossa approach
Surgical Approach Protocol
1. 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 radiotherapy
Single 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
Types
Glomus 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 Treatments
Tele - 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