Hormonal, ultrasonographic and histopathological evidence of ovarian remnant syndrome in a young desexed ferret (<i>Mustela putorius furo</i>) in the United States

Abstract A 5.5‐month‐old, commercially bred, female desexed ferret presented for vulvar swelling. Hormonal testing revealed elevations in oestradiol and androstenedione, suspicious for either adrenal disease, an ovarian remnant or ovarian neoplasia. Vulvar swelling resolved following intramuscular administration of human chorionic gonadotropin, thus excluding adrenal disease. Abdominal ultrasound identified a structure resembling a normal ovary caudal to the left kidney, which was excised and histologically diagnosed as normal ovarian tissue. Six weeks after surgery, repeat hormonal testing showed a reduction of oestradiol and androstenedione to levels appropriate for a completely desexed female ferret. Based on the scoping literature review, this is the youngest reported case of a ferret with ovarian remnant syndrome and first case report to demonstrate the combined use of human chorionic gonadotropin response, hormonal assay pre‐ and post‐definitive ovariectomy, and to present ultrasonographic and histological evidence of non‐neoplastic ovarian tissue in a young ferret with ovarian remnant syndrome.