Abstract
An approximately 46 year old female beluga from the Vancouver Aquarium presented August 7, 2012 for post mortem examination. She had not been pregnant since 1976, despite having been consistently exposed to male beluga and had a history of possible pseudopregnancies in February, 2001, February 2009, April 2011 and February 2012. On May 24, 2012, she appeared lethargic, was logging and occasionally unresponsive to trainer commands. Thermo-imaging disclosed hotspots throughout the flank. Consistently elevated progesterone, fibrinogen and sedimentation rate with reduced iron were noted by sequential blood samples and clinically pathology. Pseudopregnancy with possible pyometra or retained fetus from a prior pregnancy were considerations.
Throughout July 2012, Kavna was lethargic, spat out food, and refused to undertake behaviors. She was treated with prednisone, diazepam, itraconazole, ciprofloxacin and clindamycin. Starting August 4, 2012, LutalyseTM (PGF2 alpha) treatments were administered intramuscularly. Abdominal sonographic examinations were conducted August 5 and 6, 2012. Fluid distended structures with thickened walls were noted in the left caudal abdomen and the right ovary had indistinct associated structures, suggestive of a corpora luteum or neoplasia. Minimal reproductive structures were evident in the left caudal abdomen and the stomach was gas inflated. The liver and kidney appeared normal. Kavna succumbed later that afternoon and was presented for necropsy.
She was in fair body condition and throughout the dorsolateral aspect of her torso, there was patchy hyperkeratosis and numerous punctate erosions were evident throughout the sternum. The abdominal cavity contained approximately 20 l of dark red yellow turbid fluid with a moderate amount of yellow white flocculent material. Segmentally, there was marked dilation and nodular thickening of the right uterine horn. Throughout the adjoining mesentery and serosal surfaces of the liver, kidney and diaphragm, there were numerous variably sized sessile tan to yellow firm and occasionally mineralized masses (carcinomatosis). Proximal to the outer and inner cervices, there were solitary large oblong, 10–15 cm diameter firm submucosal masses which protruded into and virtually occluded the vaginal lumina. Representative tissues were harvested for histopathology and ancillary diagnostic studies.
Histopathology of the uterine horn revealed an adenocarcinoma with multifocal and transmural extension to the serosal surface, around the right ovary and throughout the abdominal cavity. Sections of the large nodular masses associated with cervices disclosed leiomyomas.
Endometrial carcinoma is recognized in humans with prolonged estrogenism and precancerous endometrial cystic hyperplasia and in exotic felids with long term megestrol acetate administration. This tumor has previously been reported in a wild stranded beluga, possibly related to elevated pollutants or infectious agents. In this case, the tumor appears spontaneous and of limited clinical consequence to other beluga in the habitat.
Acknowledgements
The veterinary and animal care staff of the Vancouver Aquarium including Chelsea DeColle, Gwyneth Nordstrom, Brian Sheehan and laboratory support staff of the Animal Health Center are gratefully acknowledged.
*Presenting author