Abstract
A 58-year-old woman with progressive disturbance of consciousness was admitted to our hospital. CT scans and MR images revealed a large tumor expanded to the bilateral anterior cranial fossae. The tumor was composed of two components. One containing the falx in the mid portion was expanded to the left anterior cranial fossa with calcification inside, and the other occupied the right anterior cranial fossa including some cysts. Pathological study showed fibrous meningioma (WHO grade I ) in the left component, and atypical meningioma (WHO grade II) with mitosis in the right component. It was considered to be a case of large falx meningioma, which grew rapidly with a partial malignant transformation.
