Spontaneous Tumors in the Sprague-Dawley Rat

Abstract

The pathology of 62 spontaneous tumors in 52 of 125 albino Sprague-Dawley rats, used in an experiment to determine the effects of feeding a 100 percent irradiated diet, is described. The incidence of neoplasia in rats on irradiated diet and control animals showed no significant difference. The over-all incidence was 41.6 percent. Mammary tumors accounted for the largest single group, as in the reports of most investigators. A number of neoplasms were found and described, which to our knowledge have not heretofore been reported. These consist of a cavernous hemangioendothelioma of the oviduct, 2 fibrovascular polyps of the cervix, an adenocarcinoma of the small intestine, an ependymoma, a papilloma of the choroid plexus, and a pinealoma. Primary tumors of the bone, lung, liver, thymus, adipose tissue, and male genital organs, as reported by other investigators, were not observed in our series. The incidence of lymphoid and cutaneous neoplasia was very low compared with some reports in the literature.