The "concrete" histological diagnosis of cerebral tumours of neuroectodermic origin.

The "concrete" histological criteria for establishing the benignity or malignancy of cerebral tumours of neuroectodermic origin (gliomas and medulloblastomas, respectively granulocytomas) may be thus synthetized: 1) the benign tumours have a fibrocellular structure, the neoplastic cells being relatively monomorphous; vascular hyperplasia is absent, as well as necrotic and hemorrhagic foci; 2) the malignant tumours are hyper- and polymorphocellular, the fibrillar component being reduced or absent; vascular hyperplasia as well as the presence of necrotic and/or hemorrhagic foci is a constant characteristic; the tumoral cells often infiltrate the perivascular spaces.