When to euthanize a dog with hemangiosarcoma? Hemangiosarcoma in dogs is a highly malignant tumor derived from endothelial cell lines – cells that line the inside of blood vessels. It is characterized by the rapid and aggressive development of metastases. It is more common to see it in older animals, although, occasionally, there are cases of puppies. The average… Read More »When To Euthanize A Dog With Hemangiosarcoma?