acoustic neuroma & glomus tympanicum dr. vishal sharma
TRANSCRIPT
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