Malignant meningioma of the lateral ventricle. Case report.

This 65-year-old man presented with a very rare malignant meningioma in the trigonum of the right lateral ventricle. Neurological examination showed bilateral papilledema. Magnetic resonance imaging revealed a solid, enhancing tumor in the right trigonum with a hypointense cystic component located in the center of the tumor. The lesion was totally resected via a superior parietooccipital transcortical approach. Histological examination showed an anaplastic (malignant) meningioma with architectural disarray, high mitotic activity (20/10 hpf), necrosis, and cytological atypism. As in our case, heterogeneous signal, due to necrotic tissue and frequently demonstrated on both T1- and T2-weighted sequences, is suggestive of an aggressive type of meningioma.