A case of ectopic hepatocellular carcinoma around the common bile duct in a dog

• Published in: Journal of Veterinary Medical Science Vol. 87; no. 6; pp. 702 - 707
• Main Authors: OKADERA, Ryota, OSUGA, Tatsuyuki, HIRAI, Takuya, KONNO, Ryusei, TANABE, Mika, FUKE, Naoyuki, SAITO, Eren, KANEKO, Yasuyuki, NAGANOBU, Kiyokazu
• Format: Journal Article
• Language: English
• Published: Japan JAPANESE SOCIETY OF VETERINARY SCIENCE 2025; Japan Science and Technology Agency; The Japanese Society of Veterinary Science
• Subjects: Animals; Bile ducts; Carcinoma, Hepatocellular - diagnostic imaging; Carcinoma, Hepatocellular - pathology; Carcinoma, Hepatocellular - veterinary; Cell proliferation; Common Bile Duct - pathology; Cytokeratin; dog; Dog Diseases - diagnostic imaging; Dog Diseases - pathology; Dogs; ectopic liver; hepatic malignant tumor; Hepatocellular carcinoma; Hepatocytes; Liver; Liver - pathology; Liver Neoplasms - diagnostic imaging; Liver Neoplasms - pathology; Liver Neoplasms - veterinary; Macrophages; Male; Pathology; Tumor cells; hepatic malignant tumor; dog; hepatocellular carcinoma; ectopic liver
• ISSN: 0916-7250; 1347-7439; 1347-7439
• DOI: 10.1292/jvms.25-0048

A 10-year-old, male neutered pug dog with a history of gallstones was found to have a mass near the caudate lobe of the liver upon ultrasound examination. The mass was red to dark red, multinodular, measuring 3 × 3 × 4 cm and not continuous to the liver. Histopathological examination revealed sheet-like proliferation of polygonal neoplastic cells resembling hepatocytes with mild atypia, and no portal areas were observed. The tumor cells were positive for HepPar-1 and negative for cytokeratin 7. The macrophages decreased in neoplastic lesion compared to normal area. Based on these findings, this case was diagnosed as a hepatocellular carcinoma of ectopic liver origin. This is the second reported case showing the potential for ectopic liver to develop into tumors in dogs.