The patient went on to have a repeat craniotomy and excision of this large mass.
Histology
MICROSCOPIC FEATURES: The sections show a moderately hypercellular meningioma. A well developed syncytial architecture is present in the majority of the tumour and tumour cells overall, have uniform nuclear features. However, approximately 5% of tumour cells have rhabdoid features with enlarged eccentrically located nuclei and a moderate amount of eosinophilic cytoplasm and have a diffuse sheeted arrangement. No mitotic figures or areas of necrosis are identified and there is no evidence of brain invasion. Strong progesterone receptor expression is seen in >90% of tumour cells including those with rhabdoid features. The topoisomerase labelling index varies between 6-8%.
COMMENT: Although the features in this meningioma fall short of those required for a diagnosis of atypical meningioma, the focal presence of rhabdoid features in tumour cells and the slightly elevated topoisomerase labelling index indicates a higher than usual likelihood of local recurrence
FINAL DIAGNOSIS: Meningioma with focal rhabdoid features