Spontaneous primary astrocytoma in the spinal cord of a mouse and a rat.

A spontaneous astrocytoma was observed as an incidental finding in the thoracic spinal cord of a control Charles Rivers CD-1 female mouse from a 2 yr oncogenicity study. An astrocytoma was also observed in the lumbar spinal cord of a Charles Rivers Sprague-Dawley control, female rat from a 2 yr oncogenicity study. The mouse was clinically normal and was sacrificed at the end of the 2 yr study. The rat was killed at 512 days of age because of posterior paralysis.