Fourth Ventricular Schwannoma: Identical Clinicopathologic Features as Schwann Cell-Derived Schwannoma with Unique Etiopathologic Origins

Abstract

Background. To our knowledge, this is the sixth reported case in the literature of fourth ventricular schwannoma. The etiology and natural history of intraventricular schwannomas is not well understood. A thorough review of potential etiopathogenic mechanisms is provided in this case report. Case Description. A 69-year-old man presented with an incidentally found fourth ventricular tumor during an evaluation for generalized weakness, gait instability, and memory disturbance. Magnetic resonance imaging (MRI) revealed a heterogeneously enhancing lesion in the fourth ventricle. A suboccipital craniotomy was performed to resect the lesion. Histopathological examination confirmed the diagnosis of schwannoma (WHO grade I). Conclusions. Schwannomas should be considered in the differential diagnosis of intraventricular tumors. Although the embryologic origins may be different from nerve sheath-derived schwannomas, the histologic, clinical, and natural history appear identical and thus should be managed similarly.

Intra-fourth ventricular schwannoma in pediatric age group: Report of second case in the Western literature with review of literature

“…These include pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma. [ 5 13 ] Other localization can be intraparenchymal schwannomas, which are rare and have been reported more frequently in the spinal cord than within the brain. Schwannomas exhibit a number of characteristics, albeit nondiagnostic, neuroradiological features.…”

“…They account for up to 8% of all primary brain tumors. The schwannomas in the fourth ventricle are extremely rare, but only one case of pediatric schwannoma occurring in a 7-year-old boy has been described[ 4 5 6 7 8 9 ] previously and was reported by Redekop et al . [ 9 ] In this case, the boy was managed surgically with excellent neurological outcome.…”

Schwannoma of the Fourth Ventricle: The Eighth Case Report

“…Most (95%) are extra-axial, but they can also be found within the brain and spinal cord parenchyma or ventricular system (4,16). The intraventricular location is the least common, with no more than 20 cases reported since 1950 (18), comprising 1 case in the third ventricle (17), 12 in the lateral ventricles (2, 4-8, 11-13, 19, 20, 25, 28), and 7 cases in the fourth ventricle (10,14,16,18,22,29). The first fourth ventricle schwannoma ever reported (in 1957) was malignant and diagnosed postmortem (14).…”

Supratentorial Paraventricular Schwannoma

“…Approximately 73% of the published intraventricular tumors were diagnosed in the adult population, 50% located in the lateral ventricles, the majority on the right (approximately 80%), only one case was described on the third ventricle. 7 Relatively more common in men than in women, 12 of 19 reported cases, 13 the opposite of the conventional schwannoma of the central nervous system, also peaked between the third and six decades. 15…”