Lymphoma, sometimes called lymphosarcoma, is one of two inherited cancers in the
Australian Shepherd. (The other is hemangiosarcoma.) Lymphoma is a cancer of the
white blood cells. It most frequently arises in the lymph nodes, spleen, or bone marrow.
It can also start in the gastric system, skin, or thymus gland. The most common sign is
an enlarged lymph node below the jaw or behind the stifle (knee.) Affected dogs often
are lethargic, anorexic, lose weight, or have swelling of the legs or face. Occasionally
they will drink and urinate frequently or have difficulty breathing, irritated patches on the
skin or mouth, vomiting, or dark foul-smelling diarrhea.
Prognosis varies and is somewhat dependent on the specific form of lymphoma
the dog has. Some forms respond better to chemotherapy though most dogs will
relapse after a period of remission. With additional chemotherapy a second remission
is usually possible, though of shorter duration than the first. Most dogs will eventually
die of the disease.
First-step relatives of affected dogs (parents, full and half siblings, and offspring)
should be bred only to mates with pedigrees as clear of lymphoma as possible and who
have no affected close relatives. Any dog that has had lymphoma, even if it is in
remission, should not be bred. If semen has been stored from an affected male it
should be discarded.