Abstract

Background: Primary intra-axial cerebral schwannomas are exceptionally rare benign tumors that arise within the brain parenchyma without any association with cranial nerves. Their nonspecific clinical and radiological features frequently mimic high-grade gliomas, making preoperative diagnosis challenging. Case Presentation: We report the case of a 17-year-old male who presented with recent-onset right-sided visual disturbance and bilateral early papilledema. Magnetic resonance imaging demonstrated a lobulated, contrast-enhancing left occipitoparietal intra-axial mass with restricted diffusion, hyperperfusion, extensive vasogenic edema, and adjacent calvarial remodeling, raising suspicion for glioblastoma, gliosarcoma, or pleomorphic xanthoastrocytoma. The patient underwent gross-total resection through a left occipital craniotomy. Histopathological examination revealed a well-circumscribed cellular spindle-cell neoplasm with alternating hypercellular and hypocellular areas, perivascular hyalinization, and an absence of mitotic activity or necrosis. Immunohistochemistry demonstrated diffuse positivity for S100 and SOX10, negative Olig2 staining, retained INI-1 expression, and a low Ki-67 proliferation index of approximately 5%, establishing the diagnosis of a WHO grade 1 cellular schwannoma. Conclusions: Intra-axial cerebral schwannoma should be considered in the differential diagnosis of enhancing supratentorial brain lesions in children and adolescents, particularly when imaging suggests a high-grade glioma. Definitive diagnosis relies on histopathological and immunohistochemical evaluation. Gross-total resection is associated with excellent outcomes and durable disease control, although continued radiological surveillance remains advisable given the rarity of the condition.

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