Abstract

A 13-year-old female Allen’s swamp monkey (Allenopithecus nigroviridis) presented with intermittent excessive vaginal bleeding and a history of irregular menstrual cycles. This animal had a melengestrol acetate implant left in for 6.5 years before it was removed 4 years prior to clinical presentation.

On examination, abdominal ultrasonography revealed a subjectively thickened endometrium with an irregular, mottled appearance. Additionally, three uterine fibroids (leiomyomas) were identified, ranging from 7 to 9 millimeters in diameter. The right ovary was found to have both a simple cyst and follicular cyst, and the left ovary also contained a follicular cyst.

After consultation with an OB/GYN, a treatment protocol, consisting of intramuscular injections of leuprolide acetate (Lupron Depot® 3.75 mg suspension, Abbott Laboratories, North Chicago, IL 60064 USA) monthly for six months was elected. Leuprolide acetate has been used in human patients for treatment of endometriosis and uterine fibroids. Recheck ultrasound at three months showed a decrease in fibroid diameter and resolution of all ovarian cysts. At seven months there was a normal contour to the uterine body with only one uterine fibroid remaining. Complete blood counts and serum biochemical profiles were also assessed at times of examination and found to be within normal limits during treatment.

The animal clinically had no further vaginal bleeding. Gastrointestinal side effects have been reported in humans with leuprolide acetate (product insert), and this animal had a two-day period of abdominal distention suspected to be intestinal gas that spontaneously resolved. No other adverse reactions were observed.

Acknowledgments

The authors thank the mammal and veterinary staff at the Toledo Zoo for their assistance with this case.