Presentation
CN6 palsy and partial CN7 palsy.
Patient Data
There is an extra-axial solid tumor within the left cerebellopontine angle, with regular contours, spontaneously hyperattenuating with a vivid and homogenous contrast enhancement, covering partially the IAC but not clearly expanding it, and promoting local mass effect with compression and mild displacement of the left cerebellar peduncle and midbrain. On the bone window, it is possible to spot mild reactive hyperostosis.
Left cerebellopontine extra-axial mass measuring 31 x 19 x 24mm (AP x RL x CC) demonstrates intermediate T1 intensity, T2 hyperintensity and homogenous enhancement.
The tumor extends into the left internal acoustic meatus. Associated dural tail present with extension along the inferior aspect of the tentorium and partially into the left cavernous sinus probably at the site of Dorello's canal.
Mass effect present with effacement of the adjacent pons with minimal edema present.
The 4th ventricle is mildly distorted but is not occluded and no evidence of hydrocephalus is present.
CT images show calcification within the mass and probable hyperostosis.
No further enhancing lesions detected.
Conclusion:
Left CPA angle mass demonstrates features which would be in keeping with a meningioma, with mass effect of the pons and 4th ventricle but no hydrocephalus and extension into the left IAM and left cavernous sinus. Extension into Dorello's canal presumably accounts of the patients CN VI palsy.
MICROSCOPIC DESCRIPTION: The sections show a moderately cellular meningioma focally invading into the attached dura. The tumor comprises whorls and fascicles. The tumor cells have ovoid nuclei with no significant nuclear pleomorphism. Mitoses are inconspicuous. There is no necrosis. No brain parenchyma is included in the biopsy. There is no atypical or malignant change.
DIAGNOSIS: L CPA tumor: Meningioma (WHO Grade I).
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