Differencial Pathologies Khbw

7/28/2019 Differencial Pathologies Khbw

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By:Nour-Eldin A Mohammed

Referrence:Stephan Chapman 2003


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Extra-axial area lateral to the prepontinecistern 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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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 (Gradengos

syndrome) , Malignant otitis externa


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Comprises 60-92% of CPA lesions

Involve the vestibular division of the 8th

cranialnerve


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Features of AcousticNeuroma:1. Centered over the petrous bone

2. Acute angle with the petrousbone

3. Extension into the internalauditory canal

4. Homogenous enhacement

5. No dural tail6. No calcifications


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Second most common CPA lesion 3-7 %

Arise from cap cells near arachnoid villi which

are more prominent near cranial nerveforamina 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:1. Broad base over the petrous bone2. Homogenous signal3. A small toungue extension into

the internal auditory canalwithout widening it

4. Homogenous enhacement5. dural tail6. Calcifications , psammoma

bodies7. Hyperostosis


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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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TI WI

T2 WI Proton WI

Features of Epidermoid:1. Low density Cyst with

lobulated margin2. CSF like signal (with high

signal in diffusion,flair andproton seq3. May exert extensive mass

effect4. Also occur parasellar and

rarely itra diploic


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Similar to vestibular neuoma but arises fromthe trigeminal nerve


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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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Anterior inferiorcerebellar arteryGiant aneurysm


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Differencial Pathologies Khbw

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