Hereditary renal carcinomas (RCs) develop in virtually all Eker rats by the age of one year. Investigation of extrarenal primary tumors occurring in Eker rats late in life (at 2 years) additionally revealed pituitary adenomas (17/31 = 54.8% (carrier) vs 7/32 = 21.9% (non-carrier siblings of affected animals), P < 0.01), sarcomas of the spleen (21/31 = 67.7% vs. 0/32 = 0%, P < 0.001) and sarcomas (of probable stromal origin) of the uterus (8/17 = 47.1% vs. 0/15 = 0%, P < 0.01). Thus, the Eker rat might provide a novel animal model of cancer predisposition syndromes.