Clinical, diagnostic, and pathologic features and surgical outcomes of combined hepatocellular-cholangiocarcinoma in dogs: 14 cases (2009-2021).

Abstract

OBJECTIVE: To describe the clinical, diagnostic, and pathological features and postoperative prognosis of canine combined hepatocellular-cholangiocarcinoma (cHCC-CCA). ANIMALS: 14 privately owned dogs that underwent surgical treatment. PROCEDURES: The medical records, including signalment, clinical signs, blood test, urine analysis, computed tomography (CT) findings, intraoperative findings, and pathological findings, were retrospectively reviewed in the dogs with cHCC-CCA. RESULTS: Of 306 dogs that underwent surgical removal of hepatic masses, 14 dogs (4.6%) were pathologically confirmed to have cHCC-CCA. Median age and body weight were 11.3 years and 7.3 kg, respectively. There were no specific clinicopathological findings for cHCC-CCA. CT revealed a massive hepatic mass in all dogs and the inclusion of cyst-like lesions within the mass in 13 dogs. Intrahepatic metastases were found at time of surgery in 2 dogs (14.3%). Of the residual 12 dogs, 1 dog showed postoperative formation of intrahepatic nodules suggestive of metastases and another had intrahepatic and pulmonary nodules and a forelimb skin mass, suggesting postoperative metastases. The median survival time of the patients with cHCC-CCA was 700 days (range, 10 to 869 days) after surgery. CLINICAL RELEVANCE: To the authors' knowledge, this is the first study to describe the clinical, diagnostic, and pathological features and postoperative prognosis of canine cHCC-CCA. The clinical and diagnostic features of canine cHCC-CCA might be more similar to those of HCC rather than to those of CCA, but the preoperative diagnosis differentiating between HCC and cHCC-CCA was challenging. Our study suggests that the postoperative prognosis of canine patients with cHCC-CCA is similar to that of dogs with HCC.