Focal cystic endometrial hyperplasia in a bitch.

Rapid abdominal enlargement and weight gain occurred in a four-year-old Rhodesian ridgeback bitch in late oestrus. The bitch was nulliparous. Severe cardiovascular dysfunction followed and an exploratory laparotomy was performed. A large, single, spheroid mass weighting 17 kg was located in the middle section of the left uterine horn. A diagnosis of sterile, focal, cystic endometrial hyperplasia was made from gross pathology, histopathology and bacteriology. The bitch made a complete recovery following an ovariohysterectomy.