Presentation
Headaches and falls.
Patient Data
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The large extra-axial mass ( * ) results in significant midline shift with displacement of the anterior falx towards the right along with anterior subfalcine herniation (blue arrows). Previous craniotomy is best seen on bone window (green arrows).
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 tumor and tumor cells overall, have uniform nuclear features. However, approximately 5% of tumor 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 tumor cells including those with rhabdoid features. The topoisomerase labeling 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 tumor cells and the slightly elevated topoisomerase labeling index indicates a higher than usual likelihood of local recurrence
FINAL DIAGNOSIS: Meningioma with focal rhabdoid features
Case Discussion
Meningiomas are usually cured when complete excision is achieved, however even in such cases recurrence either at the site of resection or somewhere else along the dura (field effect) is not infrequently encountered, particularly if there are atypical histological features. As such many surgeons elect to follow these patients for many many years if not for ever with yearly or biyearly MRIs.