Medulloblastomas and other neural tumours in mice treated neonatally with N-ethyl-N-nitrosourea

Newborn mice of four inbred strains were injected with a single dose of N-ethyl-N-nitrosourea. The wide range of tumours induced included a small number in the central and peripheral nervous systems. The 4 brain tumours all arose in the cerebellum. Three in one strain were medulloblastomas showing continuity with the internal granular layer. All three tumours showed diffuse infiltration through the molecular layer and continuity with densely-packed islets of cells that marginated immediately beneath the pia and closely resembled remnants of a persistent fetal external granular layer. The medulloblastomas are discussed with special relevance to the histogenesis of the equivalent tumour in man.