III.07 Anaplastic meningioma

PIII07a1 - Click here to make me bigger
PIII.07.a1 Anaplastic meningioma (HE x40). Intraspinal meningothelial meningioma (with whorls and psammoma bodies) containing anaplastic foci (increased cellularity, chromatin-rich, high nucleoplasmic index, some mitoses, necroses). Owing to their natural encapsulation and generally superficial localization, anaplastic meningiomas are often amenable to total resection, provided they have not invaded the surrounding tissues. The prognosis for anaplastic meningiomas is thus not necessarily unfavorable, and depends on the total extent of resection. Certain authors reserve the term "anaplastic" for those meningiomas that show signs of invasion; meningiomas that present histologic features of anaplasia but do not invade the neighboring tissues are merely considered "atypical". Meningiomas can slowly erode the skull and invade the epicranium, without presenting any histologic feature of anaplasia.