Of 185 endocrine imbalance female rats, 16 survived over 3 years. Leiomyomas were present in 4 of these 16 animals. One animal had multiple tumors; 2 were located in the middle and lower third of the right cornu, and a third was near the cervical end of the left cornu. The other 3 animals had single tumors. In one of these the tumor was located in the right cornu. In the other 2 it was in the left cornu. It is believed that the chronic estrogen stimulation resulting from the endocrine imbalance increases the chance of smooth muscle tumor formation.
This investigation has been supported by grants from The Anna Fuller Fund and the National Cancer Institute (U.S.P.H.S.).