Hyperandrogenism associated with an ovarian remnant in a spayed female cat.

CASE SUMMARY: An 11-year-old female, reportedly spayed, domestic shorthair cat was examined for a 4-month history of weight loss, aggression, urine spraying, malodorous urine and estrus-like behavior. Physical examination revealed thickened skin, a mildly prominent vulva and confirmed malodorous urine. On abdominal ultrasonography, a 6 mm hypoechoic nodule was found in the left cranial abdomen. An adrenocorticotropic hormone (ACTH) stimulation test with adrenal panel revealed elevated serum concentrations of androstenedione and testosterone pre- and post-cosyntropin stimulation, mildly decreased cortisol pre- and post-cosyntropin stimulation, and decreased resting aldosterone. Exploratory laparotomy was performed and a cystic, nodular mass was found in the region of the left ovary. The mass was surgically removed and submitted for histopathology; results were conclusive for an ovarian remnant with an intact corpus luteum and non-neoplastic parovarian cysts. Previously observed clinical signs resolved within two weeks of ovariectomy. A follow-up ACTH stimulation test with adrenal panel 6 weeks postoperatively revealed normalization of serum androstenedione, testosterone and cortisol concentrations. Four years postoperatively, at the time of writing, the cat remains free of clinical signs.

RELEVANCE AND NOVEL INFORMATION: We are unaware of any previously reported cases of non-neoplastic ovarian remnants associated with clinically relevant hyperandrogenism. A non-neoplastic ovarian-dependent hyperandrogenism should be included as a differential diagnosis of spayed female cats showing aggression and urine spraying behavior.