Spontaneous neoplastic lesions in Harlan Sprague-Dawley rats

In a 24-months study, the spontaneous tumour spectrum of the Hsd:Sprague-Dawley stock was examined. Pituitary gland tumours were found in 20 % of the males and 39 % of the females. This relatively low incidence, compared to other SPRD stocks, had little effect on the survival of females (50 %), due to the high incidence (76 %) of mammary gland tumours (predominantly fibroadenomas) that resulted in unscheduled sacrifices of many females. Other common neoplasms in Hsd: Sprague-Dawley rats were benign medullary tumours (27 % in males, 11 % in females), C-cell adenomas (23 % in males, 28 % in females), and endometrial stromal polyps (22 % in females).