Intraventricular meningiomas: a consecutive series of 22 patients and literature review.

Intraventricular meningiomas (IVMs) are rare tumors of which the majority is located in the lateral ventricles. Most published series on the subject includes only a few patients. We analyzed our series of IVMs with a special interest in clinical features, outcome, and complications related to surgery. Twenty-two patients underwent resection of IVMs from 1990 to 2010 at Oslo University Hospital. Surgical and medical records were retrospectively analyzed. The IVMs were located in the trigonum of the lateral ventricles (20/22), in the third ventricle (1/22), and in the fourth ventricle (1/22). The most common symptoms and signs were headache, vertigo, nausea/vomiting, mental disturbances, balance impairment, and corticospinal tract signs. Visual field deficit was present preoperatively in two patients. Tumors of the lateral ventricles were resected via a transcortical parieto-occipital approach; the tumors in the third and fourth ventricle via a frontal transcortical and suboccipital route, respectively. Complete tumor resection was achieved in all but one case. Histology was WHO grade I in 20/22 and grade II in 2/22. Surgical mortality was 0%. Most symptoms and signs resolved after surgery. The most common complication was visual field defect: four patients developed new-onset contralateral homonymous quadrant anopia and one patient developed hemianopia. Symptomatic IVMs should be resected, and most symptoms and signs resolve after surgery. The main challenge is to avoid damaging the geniculucalcarine tract when resecting IVMs in the trigonum. Preoperative diffusion tensor imaging-based tractography to map the geniculocalcarine tract could be a useful adjunct in the preoperative planning before selecting the surgical approach.