martedì 1 maggio 2007

Cerebellar pontine angle meningioma


Broad based extra-axial mass located in the left cerebellar pontine angle extending to the porous acousticus but not entering the internal auditory canal. The mass demonstrates isointensity relative to gray matter on T1-weighted and mildly increased signal on T2-weighted sequences. The mass enhances homogeneously with contrast. There is moderate mass effect on the brachium pontes.

Differential diagnosis for a cerebellar pontine angle (CPA) mass:
- Meningioma
- Schwannoma
- Dermoid
- Epidermoid
- Metastasis
- Sarcoid
- Arachnoid cyst
- Lipoma
- Aneurysm

Diagnosis: Cerebellar pontine angle meningioma


CPA meningiomas are often positioned eccentric to the porous acousticus

CT findings: NECT
- 70% hyperdense, 30% isodense; 25% calcified
- Hyperostosis or permeative bone changes
- IAC flaring
+ CECT: 90% strong uniform enhancement, 10% inhomogeneous

MRI findings (See table below)

- Dural vessels supply tumor center and pial vessels supply the rim
- Sunburst pattern of enlarged dural feeders
- Vascular stain in venous phase
- Arteriovenous shunting may be present

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