Ependymoma in a rat.

Pathological examination was performed on a male 196-day-old Sprague-Dawley rat with hindrance of the motility. A tumor was found to locate in the right lateral ventricle. It was poorly demarcated, and was reddish gray in color. The tumor cells were pleomorphic, fusiform or polygonal in shape and varied in size, sometimes with formation of pseudorosettes. The tumor was diagnosed as ependymoma.