Presentation
Altered sensation left side of face.
Patient Data
A sharply circumscribed tumor lies within the left prepontine cistern, extending into the cerebellar pontine angle cistern. A compressed and laterally displaced cisternal portion of the left fifth nerve is shown, the tumor extends into Meckel's cave, and is associated with vivid contrast enhancement, and is mildly hyperintense on T2-weighted imaging. The clivus is not involved. The tumor extends to the anterior margin of the internal acoustic canal and is otherwise not related to the seventh or eighth nerve complex. Inferiorly it extends to just inferior to the pontomedullary junction, medially to the midline, and in contact with the basilar artery, and partially encircling the SCA.
Cerebral parenchymal signal intensity and architecture are otherwise within normal limits. Ventricles and sulci are age-appropriate and normal. The bone of the central skull base is unremarkable. Mild distortion of both globes is incidentally noted.
Conclusion:
The differential diagnosis lies between a schwannoma of the left fifth nerve, or a meningioma of the petrous apex extending into Meckel's cave. The visualization of displaced fifth nerve, a small dural tail, and inferior extension makes meningioma more likely.
Case Discussion
The patient went on to have a resection, confirming the diagnosis of meningioma.
Histology
The sections show a moderately cellular meningioma. The tumor forms whorls and fascicles with psammoma bodies. The tumor cells have ovoid nuclei with no nuclear pleomorphism. Mitoses are inconspicuous. There is no necrosis. No brain parenchyma is seen. There is no atypical or malignant change.
FINAL DIAGNOSIS: meningioma (WHO Grade I).
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