Endometrial polyps in the bitch: a retrospective study of 21 cases.

Endometrial polyps (EPs) are tumour-like lesions reported frequently in domestic carnivores. The present report describes the clinical and pathological features of EPs in 21 bitches. Most affected bitches had a regular reproductive history. Five bitches had no clinical signs and eleven showed clinical signs of pyometra. Four bitches had a large EP which resulted in compression of the abdominal viscera. One bitch had an acute uterine torsion. A clinical diagnosis of EPs was only made when the lesions were large and identified by abdominal palpation or ultrasound. Grossly, the EPs were 5-25 cm in diameter and were single, sessile or pedunculated. They were often associated with cystic endometrial hyperplasia. Microscopically, the EPs were fibroglandular with the stroma sometimes being haemorrhagic and infiltrated by inflammatory cells. In one case, there were areas of stromal smooth muscle and epithelial squamous metaplasia, which may have been consistent with preneoplastic change.