Uterine Adenocarcinoma in a Lionhead Rabbit

An 8-year-old, female lionhead rabbit with clinical sign of hematuria and vaginal discharge with/without blood was submitted to a local animal hospital. On exploratory laparotomy, three round to oval masses were observed in both uterine horns. The lumen of uterus was severely obstructed and distorted because of massive neoplastic proliferation. Histopathologically, the uterine masses revealed papillary projections along with irregular glandular structures into the lumen. The neoplastic foci were composed of numerous irregular sized neoplastic glands originated from uterine glands. These neoplastic cells showed very strong invasive tendency to muscle layer, therefore emboli of neoplastic cells were located in lymphatics. According to immunohistochemistry, the tumor cells in uterine masses demonstrated strong positive signals for cytokeratin, but negative for vimentin. Based on the gross, histopathologic and immunohistochemical features, this case was diagnosed as uterine adenocarcinoma in lionhead rabbit.