Differential%20Diagnosis%20of%20Cerebellopontine%20Angle%20lesions

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Differential Diagnosis of Cerebellopontine Angle
lesions

• By
• Nour-Eldin A Mohammed
• ReferrenceStephan Chapman 2003

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Cerebellopontine Angle

• Extra-axial area lateral to the prepontine
  cistern containing CSF, arachnoid tissue, cranial
  nerves and their associated vessels.
• Borders
• Medial lateral surface of the brainstem
• Lateral petrous bone
• Superior middle cerebellar peduncle
  cerebellum
• Inferior arachnoid tissue of lower cranial
  nerves
• Posterior cerbellar peduncle

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Differential Diagnosis

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 tumourseg, glomus
   tumors,metastases,cholesterol granuloma
8. Skull base infectionosteomyelitis of the petrous
   apex (Gradengos syndrome) , Malignant otitis
   externa

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Acoustic Neuroma

• Comprises 60-92 of CPA lesions
• Involve the vestibular division of the 8th
  cranial nerve

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• Features of Acoustic Neuroma
• Centered over the petrous bone
• Acute angle with the petrous bone
• Extension into the internal auditory canal
• Homogenous enhacement
• No dural tail
• No calcifications

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Meningioma

• Second most common CPA lesion 3-7
• Arise from cap cells near arachnoid villi which
  are more prominent near cranial nerve foramina
  and venous sinuses.
• Usually arise from posterior surface of the
  petrous bone and usually do not extend into IAC

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• Features of Meningioma
• Broad base over the petrous bone
• Homogenous signal
• A small toungue extension into the internal
  auditory canal without widening it
• Homogenous enhacement
• dural tail
• Calcifications , psammoma bodies
• Hyperostosis

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Epidermoid Cyst

• Accounts for 2-6 of CPA masses
• Congenital lesions that present in adulthood
• Rests of ectodermal tissue containing stratified
  squamous lining and keratin
• May arise within the temporal bone or in the CPA

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• Features of Epidermoid
• Low density Cyst with lobulated margin
• CSF like signal (with high signal in
  diffusion,flair and proton seq
• May exert extensive mass effect
• Also occur parasellar and rarely itra diploic

TI WI
T2 WI
Proton WI
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Arachnoid Cyst
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Trigeminal Neuroma

• Similar to vestibular neuoma but arises from the
  trigeminal nerve

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Vascular Lesions

• 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

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Basilar artery Dolicoectasia
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AICA LOOP
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Anterior inferior cerebellar artery Giant
aneurysm
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Glomus Jugulare
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