Periventricular Intraparenchymal Schwannoma

Abstract

A 60-year-old male presented with a rare case of periventricular schwannoma. Imaging studies revealed a partially calcified, well-enhanced tumor in the periventricular area of the left frontal horn. The preoperative diagnosis was low grade glioma, but postoperative pathological findings revealed that the tumor was schwannoma. Most intraparenchymal schwannomas are benign, so total extirpation is usually curative. However, this uncommon neoplasm is difficult to distinguish from mimics, especially low grade gliomas, with only preoperative radiological findings or intraoperative pathological findings. Based on our experience and analysis of the characteristic radiological and pathological features in previous cases, we suggest that an accurate intraoperative diagnosis is possible. The key element is the combination of correct interpretation of the intraoperative pathology analysis and careful evaluation of the preoperative radiological studies. An appropriate intraoperative judgment is important, because the treatment, including the surgical management, would be totally different for schwannoma and glioma.

An atypical case of intracerebral schwannoma

“…They were reported to originate from the ventricular and periventricular structures. They have also been described in the cerebellar hemispheres,vermis and brain stem [ 4 , 5 ].…”

“…Khoo HM et al reported that calcification was noted in 29%, cyst formation in 68% and peritumoral edema in 87.5% of the cases. These characteristics appear to be more frequent in intracerebral schwannomas than in acoustic neurinomas and peripheral schwannomas [ 4 ].…”

“…Most of these schwannomas arise from the vestibular portion of the VIIIth cranial nerve and less commonly, with descending order of frequency, from the Vth, IXth, Xth, and VIIth cranial nervesn [ 2 ], intraparenchymal schwannomas not related to cranial nerves are very rare, it represent less than 1%. To our knowledge, about 70 cases have been reported so far since the first case reported by Gibson et al in 1966 [ 3 , 4 ].…”

Fractionated Radiosurgical Treatment of Intracerebral Schwannoma: A Case Report and Literature Review

“…Intracranial schwannomas (ICS) usually arise from the vestibular portion of the eighth cranial nerve, less commonly from other cranial nerves including rare cases of olfactory and optic nerve schwannomas, and account for $8% of all primary intracranial tumors in adults. [1][2][3] Only a few case reports unrelated to cranial nerve intraparenchymal schwannomas are available since 1966 when the first case was described by Gibson et al [4][5][6][7][8][9][10] ICS constitutes $0.8% of all intracranial nerve sheath tumors. 11 In some cases, an associated neurofibromatosis (NF) was found.…”

“…15 Preoperative differential diagnoses include pilocytic astrocytoma, pleomorphic xanthoastrocytoma, ganglioglioma, meningioma, and glioblastoma. 10,16 Therefore, the primary treatment modality is often open surgery to gain histopathological verification and to select the right treatment modality.…”