9 - Other Glial Neoplasms

Three rare glial neoplasms that do not belong to astrocytic or ependymal families, yet have unique and readily recognized histologic patterns, defining molecular and immunohistochemical features, and clinicopathologic settings, include angiocentric glioma, astroblastoma, and chordoid glioma. Angiocentric gliomas are low-grade, supratentorial tumors of childhood and young adulthood that are associated with seizures and composed of cytologically bland, spindled, and monomorphic glioma cells surrounding cortical and subcortical blood vessels. Astroblastomas are solid, well-circumscribed cerebral hemispheric neoplasms of children and young adults that are defined histologically by the presence of astroblastic pseudorosettes, composed of broad, nontapering processes extending to central vessels. Chordoid gliomas are a histologically low-grade tumor that occur almost exclusively in the region of the third ventricle and are composed of GFAP-positive epithelioid tumor cells arranged in cords and clusters with a myxoid stroma.