Types of Canine Splenic Tumors: Are Splenic Tumors Always Malignant?

Masses in the spleen occur primarily in middle-aged to older dogs. In many cases, splenic masses consist of only benign hematomas or fibrous nodules.

However, these masses can sometimes be highly malignant forms of cancer, especially vascular cancer known as hemangiosarcoma.

Types of Canine Splenic Tumors: Are Splenic Tumors Always Malignant?

The spleen

The spleen is a highly vascular organ that sits in the left, in front of the abdomen. It functions as a blood reservoir and as a filter to remove old blood cells from circulation. The spleen also contains lymph tissues and can become enlarged in leukemia or lymphoma.

Dogs with tumors of the spleen often develop a bloated or pendulous abdomen as this organ enlarges. 

These dogs may otherwise appear normal or develop generalized signs of lethargy and loss of appetite. In some cases, the tumor can bleed into the abdomen (filling the belly with blood) and can even rupture suddenly, leading to rapid internal bleeding, collapse, and shock. In addition, malignant cancers such as hemangiosarcoma can spread to nearby organs such as the liver, so affected dogs can also develop liver problems. Anemia in dogs is a common finding with hemangiosarcoma so that dogs become quickly tired and develop pale gums.

Diagnosing splenic tumors

Your veterinarian may be able to feel a splenic mass by palpating the abdomen. 

However, they will want to use abdominal x-rays or ultrasound to pinpoint where the problem lies in most cases. In the case of a bleeding tumor, your vet may also want to draw fluid from the abdomen. Blood work may be needed to gauge the degree of anemia and to rule out other problems.

Treatment of splenic tumors

The treatment of choice for splenic tumors is the surgical removal of the spleen. 

Your vet will want to send a sample of the removed organ for histologic examination to determine if the tumor is benign or malignant. In the case of benign tumors, surgery is curative, and treated dogs usually get along well without a spleen. In the case of malignant tumors, surgery may not slow the spread of cancer, but it does remove the discomfort caused by the bloated belly, as well as the risk of bleeding. Unfortunately, chemotherapy is not usually an effective treatment for hemangiosarcoma, and dogs with this form of cancer have a poor long-term prognosis.

Related articles:
Early Signs of Splenic Tumors: What You Probably Didn’t Know about Splenic Tumors in Dogs
Canine Immune System: Spleen – Why Does The Spleen Get No Respect?
Should I Choose Surgery for My Senior Dog?

Further reading:
Splenic Masses in Dogs (Splenectomy)

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