Third ventricular atypical meningioma which recurred with further malignant progression

Meningiomas in the third ventricle are rare, with only very few cases reported in the literature. We report a case of primary third ventricular anaplastic meningioma in a 49-year-old man who presented with progressive weakness of the left limbs and headache. Magnetic resonance imaging revealed a tumor which seemed to arise from the right thalamus and extending into third ventricle. The tumor was heterogeneously enhanced with gadolinium. It was totally removed by right transventricular-subchoroidal approach. The lesion was intraoperatively found to be whitish hard and embedded in right thalamus, but had attachment to choroid plexus near foramen Monroi with narrow interface. The histological diagnosis was atypical meningioma, WHO Grade II. Lesion recurred 20 months later and was resected via the same approach, which turned out to be papillary meningioma, WHO Grade III. The patient had second recurrence 23 months after second surgery which was operated and the final diagnosis was anaplastic meningioma (WHO Grade III). Literature review showed meningioma of the third ventricle is quite exceptional and more than half of the cases were aggressive subtypes (Grade II or III).