A form of cancer that originates in the endothelium, which
is the lining of blood vessels and spleen. These tumors are highly
malignant and can be found almost anywhere in the body. The
spleen, pericardium and heart are prone to be affected.
These tumors are most common in medium-sized or large breeds
of middle aged or older dogs but can occur in any breed, including
cross-breeds. German shepherds are reported to be more susceptible
to this form of cancer than most dog breeds. The Golden Retriever
also seems to have a higher than normal incidence.
Quite often there is little warning of the presence of these
tumors before severe clinical signs are seen. An estimate of the
average time from discovery of the tumor until death occurs in
affected dogs is six to eight weeks.
The most common initial symptoms include visible bleeding,
usually in the form of nosebleeds, and signs associated with blood
loss, such as weakness, tiring easily, paleness to the mucous
membranes of the mouth and eyes, increased respiratory rates, and
abdominal swelling. In some cases, dogs just suddenly die with no
clinical signs observed at all.
If a tumor in the spleen is found when it is small, it may
be possible to remove the spleen or remove tumors found near the
heart in order to prolong the dog's life. However, most often
these tumors have spread by the time they are identified.
According to published papers, the average survival time in dogs
with Hemangiosarcoma is only three to four months.