Spontaneous brain tumours in Sprague-Dawley rats.

Data were collected over a 5-yr period on brain tumours occurring spontaneously among Sprague-Dawley-derived rats in the HRC laboratories. Gliomas, like meningiomas, tended to occur more among males than in females, and in general appeared to be lesions of older rats. Astrocytic tumours of rats were less differentiated than those in man. The characteristic patterns of human glioblastoma multiforme were not observed in this series. Most of the astrocytomas were located in the cerebral areas. Secondary deposits observed in brain included those from tumours of Zymbal's gland, squamous-cell carcinoma, mammary adenocarcinoma, osteosarcoma and lymphoreticular neoplasms.