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Washington University Experience | NEOPLASMS (MENINGIOMA) | Anaplastic | 16A2 Meningioma, Anaplastic (Case 16) H&E3

This is a meningeal tumor composed predominantly of sheets of meningothelial cells with enlarged, hyperchromatic nuclei, occasional intranuclear cytoplasmic invaginations, macronucleoli, and variable amounts of eosinophilic cytoplasm. A portion of the tumor shows a loose, fibrous matrix with individual tumor cell streaming. There is elevated mitotic activity throughout the tumor, with multiple areas showing more than 20 mitoses/10HPF. Abundant apoptotic debris, as well as foci of micronecrosis and geographic necrosis is identified. In addition, multiple foci of brain invasion by finger-like extensions of tumor are noted.

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