Giant intra-axial calcifying pseudoneoplasm of the neuraxis mimicking a high-grade glioma: A case report

INTRODUCTION: Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare benign lesion that can mimic malignant neoplasms. CASE PRESENTATION: A 19-year-old woman presented with long-standing seizures and severe headache. Magnetic resonance imaging revealed a giant intra-axial mass (8.3cm) in the right hemisphere with calcifications and mass effect, suggestive of a high-grade glioma. Complete surgical resection was performed. Histopathological examination showed a fibrillary stroma with abundant dystrophic calcifications, without atypia or mitotic figures. Immunohistochemistry demonstrated positivity for GFAP and S100 and negativity for EMA in the lesion, with a low proliferative index (Ki-67 <1%), confirming CAPNON. CONCLUSION: CAPNON is an important differential diagnosis of calcified lesions. Although its radiological appearance may be aggressive, it is a benign lesion, and complete surgical resection is usually curative.