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Washington University Experience | NEOPLASMS (MENINGIOMA) | Anaplastic | 7B2 Meningioma, anaplastic (Case 7) H&E 1.jpg
Although some areas exhibit fascicles and whorls, much of the tumor tissue appears in hypercellular sheets, with multifocal spontaneous necrosis, sparse foci of 'small cell change,' and a few areas exhibiting clear cell pattern. Occasionally, these sheets are interrupted by markedly hypercellular nodules with papillary architecture; however, in other areas (approximately half of the tumor tissue), pseudopapillary growth predominates with abundant perivascular pseudorosettes. Mitotic activity is brisk in papillary areas, ranging up to at least 22 per 10 contiguous high power (40x objective) fields. Adherent gliotic brain tissue is noted in several areas and, in some areas, brain invasion.
