Supratentorial intraventricular schwannoma with hydrocephalus in a teenager

Introduction: A 16-year-old girl, white, presented with a three-month history of progressive headache, nausea and vomiting. Suddenly appeared left hemiparesis and one seizure episode. Her neurological examination revealed left hemiparesis and bilateral papiledema. The Magnetic Ressonance Image of the brain revealed a large solid and heterogenous lesion within the right lateral ventricle with associated hydrocephalus and shift of midline structures. Also identifying signs of compression of the midbrain and obliteration of the right quadrigeminal cistern. Pathologic evaluation demonstrated densely packed fascicles of spindle cells with elongated nuclei. These were mixed with areas of loosely packed, hypocellular foci of spindle cells with small, round nuclei within myxoid matrix. Positive S-100 staining confirmed the Schwann cell origin of the tumor.

Discussion: Schwannomas account for 8% of all primary brain tumors. Most of it are associated which cranial nerves, mostly VIII, and located in the cerebellopontine angle. Currently, the etiology of ventricular schwannomas is unknown. Nerve fibres of the central nervous system are not invested with a Schwann cell corvering. Therefore, rarely schwannomas have been noted in the ventricle. Those ventricular schwannomas are localizated in the lateral venticle. The tumor mainly appears as a solid and cystic space-occupyng lesion within lateral ventricle. The main differential diagnoses include astrocytoma, cystic meningeoma, and choroid plexus tumors. On MRI, the tumor mostly appears to be low to isointense on T1-weighted images, of mixed signal intensity on T2 weighted images, and show variable contrast enhacement. The pathology generally reveals a spindle cell tumor with focal nuclear polymorphism without significant mitotic activity. No necrosis or vascular proliferation were seen. On immunohistochemical, the tumor cells show an intense diffuse positive reaction for CD57 and positive reactions for GFAP, EMA, and nuclear and cytoplasmatic S100 proteín. The treatment is a complete ressection. Chemoterapy and radioterapy are rarely indicated. Mainly in malignant intraventricular schwannomas, which are rare.

Final Comments: We report a case of a ventricular schwannoma in the lateral ventricle, presenting with hydrocephalus. When possible, total resection is the treatment of choice. Intraventricular schwannoma is extremaly rare and few cases are reported in the literature.