Histologic appearance of meningioma, WHO grades 1-3

(A) Transitional meningioma (grade 1) showing characteristic cellular whorls; intranuclear pseudo-inclusions are visible in some cells.
(B) Chordoid meningioma (grade 2) with cohesive epithelial-like cords of cells; small foci of more typical arachnoidal differentiation are found in most of these tumors.
(C) Anaplastic meningioma (grade 3) consisting of pleomorphic arachnoidal cells with a high mitotic rate; foci of necrosis are widely distributed throughout most anaplastic meningiomas.