Hepatocellular carcinoma (HCC) is the most common primary liver cancer in dogs. It can present as a single mass, multiple nodules, or diffuse spread throughout the liver, which increases the risk of metastasis. The main treatment options are surgical removal, metronomic chemotherapy, and/or Palladia. The prognosis is generally good for the single, massive form after surgery, but consulting a veterinary oncologist is recommended for all cases.