Abstract

Background:
Hepatic cholangiocarcinoma is a malignant neoplasm originating from the epithelium of the bile ducts, characterized by infiltrative growth and high metastatic potential. It presents with nonspecific clinical signs, such as abdominal distension, weight loss, and lethargy, which makes early diagnosis difficult.

Case Description:
A 13-year-old spayed female Dachshund dog was presented with abdominal distension. Physical examination revealed marked abdominal pain and abdominal enlargement. Ultrasonography identified a large cavitary structure in the liver, and thoracic
radiography revealed a pulmonary mass. Computed tomography confirmed a massive hepatic neoplastic process without invasion of the caudal vena cava or portal vein. Exploratory celiotomy followed by hepatic lobectomy of the left lateral lobe was performed with palliative intent, aiming to achieve significant clinical improvement and enhanced quality of life. Histopathological examination confirmed a massive-pattern hepatic
cholangiocarcinoma. Three months after surgery, follow-up imaging examinations revealed a new hepatic mass, without progression of the pulmonary mass. After six months, the patient developed clinical deterioration compatible with paraneoplastic syndrome and died under palliative care.

Conclusion:
Diagnostic imaging and histopathological findings contributed to the characterization of massive cystic hepatic cholangiocarcinoma in this dog. However, the advanced stage of the disease at diagnosis and the lack of characterization of the
pulmonary lesion limited complete disease assessment. Further studies and additional case reports are warranted.

Key words: Bile duct; Dog; Liver; Neoplasm.