Spleen Tumor in Dogs

By Betty Lewis

Anytime you hear the word "tumor" pertaining to your dog it's a sobering experience. If you hear it combined with the word "spleen," you may wonder what it means because the spleen is an organ that doesn't get a lot of attention. Despite its importance, your dog can live without his spleen, meaning a splenectomy is the treatment of choice for a dog with a spleen tumor. The prognosis depends on the type of tumor.

The Spleen's Work

Located near the stomach, the spleen is comprised of two types of tissue: red and white pulp. Think of the red pulp as a refuse transfer station, recycling some things -- iron and proteins -- and discarding others -- worn out blood cells. It's also the only other manufacturer of red blood cells besides bone marrow. The white pulp contains large numbers of immune system cells to help provide immunity by destroying infectious microorganisms.

Splenic Tumors

Splenic tumors are fairly common in older dogs. Boxers, golden retrievers, German shepherds, Skye terriers, Portuguese water dogs, Bernese mountain dogs and flat-coated retrievers are among the breeds most at risk for developing a splenic tumor. Poor circulation or bleeding within the spleen, known as a hematoma, may cause enlargement of the spleen. Other causes of enlargement of the spleen include excessive breakdown of blood cells, tissue overgrowth of lymphoid cells or immune cells with fibrous tissue, or splenitis, an inflammation of the spleen.

There are several types of cancer in the spleen, including those affecting the blood vessels. Hemangioma is nonspreading cancer, while hemangiosarcoma is malignant. Lymphoma, lymphosarcoma, leukemia and mastocytoma -- all white blood cell cancers -- also may affect the spleen, though they are more common in cats. Spleen tumors in dogs tend to be located in the red pulp -- the hemangiosarcoma and hemangioma.

Symptoms of Spleen Tumors

As the spleen grows in size, it often presents as swelling in a dog's abdomen. When it puts pressure on the dog's stomach, it may result in loss of appetite and vomiting. Other symptoms of a spleen tumor include weight loss, fever, lethargy, bits of bleeding on the skin or gums, diarrhea, incoordination, increased urination, dementia, rapid heartbeat and anemia. If the tumor grows rapidly, it may rupture, causing life-threatening breathing difficulties. A dog's lymph nodes may swell as well.

Diagnosing a Spleen Tumor

Your vet may suspect a splenic tumor and though radiographs and ultrasound are helpful for detecting tumors, they won't distinguish between excess tissue growth and cancer. Blood work won't confirm the presence of cancer either since not all tumors have cancer cells in the blood. Exploratory surgery to obtain tissue samples is necessary to identify the type of tumor definitely, as well as give an indication of prognosis.

Treatment and Prognosis

The best option for treatment of a splenic tumor is surgery to remove the organ. If the tumor is malignant, the cancer has spread, however surgery will slow the cancer's progress. Chemotherapy may be helpful in achieving remission for rapidly dividing smaller tumors.

The prognosis for splenic tumors depends on the type of tumor. The benign hemangioma should be cured after the spleen's removal. However, hemangiomas can be difficult to differentiate from hemangiosarcoma, which may be present in other organs, developing towards malignancy. In the case of hemangiosarcoma, which is highly malignant, survival times vary, averaging around three months post-surgery to as long as nine months.

Doing nothing is always an option, however, the tumor will continue to grow from the red pulp's blood vessels. Eventually it will rupture causing splenic hemorrhage, which can result in life-threatening blood loss.