Morphology of spontaneous brain tumors in the rat.

In lifespan studies of 2,242 rats of three strains, 32 neoplasms were identified in brain, meninges and pineal gland. They were astrocytoma (16 Wistar, three Sprague-Dawley), ependymoma (four Osborne-Mendel), meningioma (two Osborne-Mendel, one Wistar), pinealoma (two Osborne-Mendel), reticulosis (two Wistar), oligodendroglioma (one Wistar), and gliomatosis (one Wistar).