Diffuse leptomeningeal neuroepithelial tumor: 9 pediatric cases with chromosome 1p/19q deletion status and IDH1 (R132H) immunohistochemistry.

Leptomeningeal dissemination in children is typical of high-grade, and occasionally low-grade, neoplasms. Rare cases of widely disseminated oligodendroglia-like leptomeningeal tumors, sometimes with associated spinal cord lesions, have been described that respond to treatment and follow an indolent