Splenic Tumors (Including Hemangiosarcoma)

What is it?

The spleen is a blood-filtering organ in the abdomen, and it is the most common site of vascular (blood-vessel) tumors in dogs. A hemangioma is benign, much like a large blood blister. A hemangiosarcoma is a cancer that can spread to other organs. Up to 70% of dogs with splenic tumors have hemangiosarcoma; the rest have a hemangioma or another tumor such as lymphoma. Large breeds such as German shepherds, Labrador retrievers, and golden retrievers are predisposed, but dogs of any size can be affected.

What signs should I watch for?

Splenic tumors may cause no signs until they rupture, which can happen without any injury. Bleeding into the abdomen causes lethargy, weakness, collapse, poor appetite, and a swollen belly. Severe untreated bleeding can be fatal.

How is it diagnosed and treated?

Abdominal ultrasound often finds the tumor. Removing the spleen (splenectomy) both treats the tumor and prevents further bleeding, and the tissue is sent to a pathologist to identify the tumor type. With hemangiosarcoma, tests such as bloodwork, urinalysis, clotting tests, X-rays, and ultrasound look for spread, and chemotherapy is usually recommended. If your dog has a known splenic mass, keep them quiet, watch for signs of bleeding, and avoid medicines that increase bleeding risk, such as NSAIDs, before surgery.

Can it be prevented, and what's the outlook?

• There is no known way to prevent these tumors.
• Hemangiomas have a good outlook once removed.
• Hemangiosarcoma has a guarded to poor outlook because it often spreads and can bleed again elsewhere.
• Once a splenic mass is found, it is best not to delay treatment.