Hemocarcinoma: rapidly growing, highly invasive variety of cancer that occurs almost exclusively in dogs, and only rarely in cats, horses, mice, or humans (vinyl chloride toxicity). It is a sarcoma arising from the lining of blood vessels; that is, blood-filled channels and spaces are commonly observed microscopically. Most common clinical signs of visceral hemangiosarcoma include loss of appetite, arrhythmias, weight loss, weakness, lethargy, collapse, pale mucous membranes, and/or sudden death. An enlarged abdomen is often seen due to hemorrhage. Metastasis is most commonly to the liver, omentum, lungs, or brain.

Leukemia: cancer of the body's blood-forming tissues, including the bone marrow and the lymphatic system. Rapidly growing types of leukemia may cause symptoms that include fatigue, weight loss, frequent infections, and easy bleeding or bruising.