Transcript Differential Diagnosis of Cerebellopontine Angle lesions

By:
Nour-Eldin A Mohammed
Referrence:Stephan Chapman 2003
Extra-axial area lateral to the prepontine
cistern containing CSF, arachnoid tissue,
cranial nerves and their associated vessels.
Borders
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Medial: lateral surface of the brainstem
Lateral : petrous bone
Superior : middle cerebellar peduncle & cerebellum
Inferior : arachnoid tissue of lower cranial nerves
Posterior : cerbellar peduncle
1.
Vestibular Schwannoma (acoustic neuroma). Most Common Cause
2.
Meningioma
3.
Epidermoid cyst
4.
Trigeminal neuroma
5.
Vertebrobasilar system aneurysm
6.
Metastases
7.
Skull base/temporal bone tumours:eg, glomus
tumors,metastases,cholesterol granuloma
8.
Skull base infection:osteomyelitis of the petrous apex (Gradengo’s
syndrome) , Malignant otitis externa
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Comprises 60-92% of CPA lesions
Involve the vestibular division of the 8th cranial
nerve
Features of Acoustic
Neuroma:
1. Centered over the petrous bone
2. Acute angle with the petrous
bone
3. Extension into the internal
auditory canal
4. Homogenous enhacement
5. No dural tail
6. No calcifications
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Second most common CPA lesion 3-7 %
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Arise from cap cells near arachnoid villi which
are more prominent near cranial nerve
foramina and venous sinuses.
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Usually arise from posterior surface of the
petrous bone and usually do not extend into
IAC
Features of Meningioma:
1. Broad base over the petrous bone
2. Homogenous signal
3. A small toungue extension into
the internal auditory canal
without widening it
4. Homogenous enhacement
5. dural tail
6. Calcifications , psammoma
bodies
7. Hyperostosis
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Accounts for 2-6 % of CPA masses
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Congenital lesions that present in adulthood
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Rests of ectodermal tissue containing stratified squamous
lining and keratin
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May arise within the temporal bone or in the CPA
Features of Epidermoid:
1. Low density Cyst with
lobulated margin
2. CSF like signal (with high
signal in diffusion,flair and
proton seq
3. May exert extensive mass
effect
4. Also occur parasellar and
rarely itra diploic
T2 WI
TI WI
Proton WI
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Similar to vestibular neuoma but arises from
the trigeminal nerve
1. Vertebrobasilar dolichoectasia:
Enlongation and dilitation of the vertebrobasilar artery.
Symptomas : Facial spasm, trigeminal neuralgia
2. AICA loop
May loop over, under, or between CN VII & CN VIII.
Symptoms - vertigo
3. Giant Aneurysms
4. Hemangioma
5. Paragangliomas (may extend to CPA)
Glomus Jugulare
Glomus Tympanicum
Anterior inferior
cerebellar artery
Giant aneurysm