Mastectomy in ten mares: indications, surgical technique, complications, and long-term outcome

Abstract

OBJECTIVE To describe the indications for and surgical technique of mastectomy of mares and to describe the outcome of 10 mares that underwent mastectomy in a retrospective case series. ANIMALS 10 mares having disease of one or both mammary glands. CLINICAL PRESENTATION Medical records (1995 to 2022) from 2 university teaching hospitals were searched to identify mares that had undergone unilateral or bilateral mastectomy. Data regarding history, signalment, diagnostic tests, preoperative treatment, surgical procedure, and postoperative management were reviewed. Follow-up information was obtained by interviewing the owners by telephone. RESULTS One (n = 4 mares) or both mammary glands (6 mares) were excised for the following reasons: chronic bacterial mastitis (4), neoplasia (3), lymphangiectasia (1), pythiosis (1), and lymphoid hamartoma (1). None of the mares experienced intraoperative complications. The surgical site was closed primarily in 2 mares and left unsutured in 8 mares. Both sutured wounds developed a seroma, and 1 dehisced. The owners reported that the surgical wound, whether sutured or unsutured, was healed within 3 months. All mares returned to use for their intended purpose, but 3 mares were euthanized 2 to 4 years after surgery due to progression of disease. One mare drowned 1 year after discharge. CLINICAL RELEVANCE Mastectomy can be an effective treatment for mares suffering from disease of one or both mammary glands when the mare is refractory to medical treatment.