Intraparenchymal schwannoma in an adult presenting as a periventricular lesion of the parieto-occipital lobes: Diagnostic and surgical challenges.

Introduction: Intraparenchymal schwannomas (IS) are exceedingly rare, constituting less than 1 % of all intracranial schwannomas. To date, approximately 150 cases have been reported in the literature, with only 10 involving the parieto-occipital region. Unlike vestibular schwannomas, IS lacks an apparent association with cranial nerves and often mimics high-grade gliomas or metastatic tumors, leading to diagnostic uncertainty. Research question: How does the extreme rarity and atypical parieto-occipital location of intraparenchymal schwannomas contribute to diagnostic challenges and potential misdiagnosis? Materials and methods: A comprehensive literature search was conducted using PubMed, MEDLINE, and Google Scholar with the keyword "Intraparenchymal Schwannoma". A total of 150 previously reported cases were used for the literature. Results: We report the case of a 56-year-old female presenting with progressive dysarthria, vertigo, ataxia, and right-sided hemiparesis. MRI revealed a large left parieto-occipital periventricular lesion with mixed solid and cystic components and significant perilesional edema. Given the progressive neurological deterioration, gross total resection of the lesion was performed. Intraoperatively, the tumor exhibited a firm, well-circumscribed morphology. Histopathological examination confirmed the diagnosis of schwannoma, a finding highly unusual in this location. Conclusion: This case highlights the diagnostic challenges of IS and the importance of surgical resection in achieving favorable neurological outcomes. Given their radiological overlap with aggressive neoplasms, advanced neuroimaging, and careful surgical management are essential for optimizing outcomes. Increased awareness of this rare pathology can aid in early recognition, prevent misdiagnosis, and guide effective neurosurgical strategies.