Osseous changes and osteosacomas in mice continuously fed diets containing diethylstilbestrol or 17 beta-estradiol

In a study on the long-term effects of dietary diethylstilbestrol or 17 beta-estradiol on C3H mice, estrogens induced a proliferation of osseous trabeculae and increased the incidence and hastened the development of osteofibrotic areas in the sterna. There were 6 osteosarcomas, 2 having metastases, in 1,242 mice fed dietary estrogens over 360 days, but none in 356 untreated controls. These tumors were reviewed along with 4 early sternal osteosarcomas selected from 17 osteosarcomas (only 1 in a control) found thus in two other ongoing comparable studies. In at least 1 case, and possibly in 2 other early cases, tumors were associated with areas of osteofibrosis, and 1 tumor was probably associated with proliferation of bony trabeculae in the medullary cavity.