This is a good example of the sometimes dramatic edema that results from radiosurgery. 

Patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: The sections show a moderately cellular meningioma. The tumor forms whorls and fascicles. The tumor cells have ovoid nuclei with no nuclear pleomorphism. Mitoses are inconspicuous. There are large areas of necrosis. No brain parenchyma is included. No evidence of atypical or malignant meningioma is identified. About 20% of the tumor cells are progesterone receptor positive. The topoisomerase index is about 3%.

FINAL DIAGNOSIS: Meningioma (WHO Grade I).