Concurrent cystic endometrial hyperplasia, ovarian luteoma and biliary cyst adenoma in an aged rabbit (Oryctolagus cuniculus)：case report and literature review

ABSTRACT

A 6-year-old female nulliparous Dutch Rabbit (Oryctolagus cuniculus) was presented in shock status with a history of abdominal distention, inappetance, lethargy, polydipsia, diarrhea and weight loss since 2 weeks ago. There was no breeding history. Radiographic survey showed increased soft tissue opacity dorsal to the urinary bladder and ventral to the colon on the lateral view consistent with uteromegaly and severe intestinal distention resembling intussusceptions. Conservative treatment was failed and the animal died. In necropsy, ileocecal intussusception was noted as the main death factor. Thickened uterine endometrium in both horns was observed and the uterus was filled with mucoid fluid. Both ovaries were multilobulated and distended. On the other hand, a small cyst sized 1.5 × 2.5 cm was diagnosed on the liver surface. Several samples were obtained from lesions for histopathological evaluation. Histopathologically, dilated cystic glands of variable size lined by densely packed epithelium and hyperplasia of the endometrium resulting in irregular folds or papillar projection into the lumen were evident and the sections of ovaries revealed ovarian luteoma that composed of polyhedral cells with pale stained vacuolated cytoplasm, centrally located nuclei with distinct cytoplasmic borders and the cytoplasm of cells contain lipid droplet. The occurrence of biliary cyst adenoma was confirmed by microscopic examination of the mass that composed of multicystic space in different sizes lined by flattened to cuboidal biliary epithelium with papillary projections. These cysts were seperated by variable amount of connective tissue. The lack of postmortem investigations in aged rabbits reduced the incidence of neoplastic disease diagnosis in this species. Whereas uterine adenecarcinoma and lymphosarcoma were commonly reported in rabbits, luteoma and biliary cyst adenoma that are well described in this case report were uncommon in rabbit medicine.