Papillary cystic uterine adenocarcinoma in a New Zealand rabbit: Histopathology of a hidden reproductive threat

Abstract

A 5-year-old female New Zealand White rabbit weighing 2.4 kg was presented with a history of repeated infertility following three unsuccessful matings and progressive abdominal distension. Owing to chronic infertility and clinical deterioration, the animal was euthanised and subjected to post-mortem examination. Necropsy revealed marked enlargement of both uterine horns and the uterine body with multiple firm, irregular masses and absence of fetuses. Histopathological examination showed an endometrial neoplasm infiltrating the myometrium, composed of papillary, tubular and cystic arrangements of epithelial cells supported by fibrovascular stroma. The neoplastic cells exhibited moderate pleomorphism with low mitotic activity and no metastatic lesions were observed in other organs. Immunohistochemically, the tumor cells showed strong cytoplasmic positivity for cytokeratin-7 and moderate apical to cytoplasmic expression of epithelial membrane antigen. Based on histomorphological features, the tumour was diagnosed as papillary and cystic adenocarcinoma of the uterus.