Histopathological and immunohistochemical characterization of a unique atypical (Grade II) meningioma with dual metaplastic morphology

ABSTRACT

Atypical (World Health Organization Grade II) meningiomas exhibiting dual metaplastic differentiation are exceptionally rare. Herein, we present a case of an 80-year-old female with altered mental status, headache, and vomiting, in whom MRI revealed a heterogeneously enhancing extra-axial lesion in the left frontoparietotemporal region. Histopathological examination demonstrated meningothelial tumor cells with both lipomatous and xanthomatous changes, a mitotic index of 6–7/10 high-power fields and a Ki-67 index of 8–10%. To the best of our knowledge, no prior report has documented concurrent lipomatous and xanthomatous differentiation in a single atypical (WHO Grade II) meningioma. Accurate recognition of such uncommon histological variants is essential to avoid misclassification as lower-grade metaplastic meningiomas, thereby ensuring appropriate grading and management.