Hyperplastic endometrial polyps in the dog and cat.

Hyperplastic endometrial polyps from 17 dogs and 14 cats are described. These growths were pedunculated to broad-based and projected into the uterine lumen. They were lined by endometrial epithelium and contained cystic endometrial glands surrounded by a well-vascularized connective tissue stroma. The morphologic evidence suggests that endometrial polyps arise from focal areas of cystic endometrial hyperplasia.