FIG 1. Histopathologic specimens of a well-differentiated and malignant astroblastoma.

A, Well-differentiated astroblastomas are composed of astroblastic pseudorosettes, which are elongated tumor cells with broad or tapering processes extending to a central vessel (arrow).

B, Malignant astroblastomas contain hypercellular mitotically active regions that often display vascular proliferation or necrosis (arrowheads).