Abstract
A 14-year-old spayed female Shih-Tzu was referred to the Veterinary Medical Teaching Hospital of Konkuk University for evaluation of an abdominal mass. In diagnostic imaging, two large cystic masses were identified. The affected liver lobes were surgically resected, and the specimens were submitted for histopathological evaluation and immunohistochemical staining. The two cystic lesions were diagnosed as biliary cystadenocarcinoma (BCAC). Recurrence and regional invasion were identified on ultrasonography 36 days postoperatively. The patient died on postoperative day 271. To the best of our knowledge, previously reported case studies of BCAC in dogs presented limited clinical information. In this report, we present a detailed picture comprising a range of clinical information and histopathological examination of BCAC in a dog.