Intraventricular meningiomas: a report of 16 cases.

Meningiomas of the ventricle system are extremely rare. We report on a series of 16 intraventricular meningiomas (IVMs) treated at our institution between 1980 and 2004, with a special interest on the surgical outcome of using the intra/inter-parietal and parieto-occipital approach and the benefits of neuro-navigation. A retrospective analysis of the medical files for clinicoradiological findings, surgical interventions and surgical outcome was carried out. In 16 IVM patients with a female/male ratio of 11:5, age ranged from 24 years to 84 years (median 44 years). Duration of symptoms ranged from a few days to several years, and the cardinal symptoms were signs of increased intracranial pressure (86%), followed by corticospinal tract signs (43%), visual field defects (36%), cognitive changes (29%) and seizures (7%). The majority of tumours was located in the trigone (88%), and one was found in each the temporal horn and in the fourth ventricle. Tumour size ranged from 2.5 cm to 8 cm (median 5 cm), and the radiological appearance was uniform. The neuropathological workup revealed most IVMs as meningothelial, transitional (mixed) or lymphoplasmacyte-rich meningiomas (81%). Three tumours were classified as atypical (19%) and the MIB-1 proliferation index ranged from 1% to 40%. Complete resection was possible in all but one case. The trigonal IVMs were resected via an intraparietal/inter-parietal or parieto-occipital approach, and neuro-navigation was used in eight tumours. We encountered one perioperative death and one severely disabled patient. All other patients had a Glasgow outcome scale score of 5, and most of the pre-existing symptoms disappeared or improved after surgery. IVMs are a surgically curable tumour entity in most cases. The intraparietal/inter-parietal and parieto-occipital approach is very safe, and neuro-navigation allows early devascularisation of the tumour.