Hyperandrogenism associated with an ovarian remnant in a spayed female cat

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.

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.