Uterine Lesions in 32 Female Miniature Pet Pigs

Abstract

Thirty-two 4-month-old to 19-year-old female miniature pet pigs were spayed. Uterine lesions were present in all except 8 pigs. The 24 remaining pigs had diffuse cystic endometrial hyperplasia, of which 14 had smooth muscle tumors, including leiomyomas and leiomyosarcomas, in the uterus or broad ligament. Nodular endometrial lesions—including adenocarcinomas, adenomas, and/or adenomyosis—were present in 10 pigs, 3 of which had concurrent smooth muscle tumors. Pyometra was present in 3 pigs. In uterine sections with cystic endometrial hyperplasia, adenomyosis, or adenomas, approximately 70% of epithelial nuclei expressed estrogen receptor and progesterone receptor immunohistochemically; in adenocarcinomas, expression was 20%. Regardless of malignancy, more than 50% of nuclei in smooth muscle tumors expressed estrogen receptor and progesterone receptor. Aging was associated with the development of uterine lesions in miniature pet pigs.