Your dog can live without his spleen, but that doesn't mean it's a throwaway organ. The spleen stores blood in the "red pulp" section, which also takes old red blood cells out of circulation. When a dog has a tumor in his spleen, the vast majority of the time it's in the red pulp section.
Once in a while, a spleen develops a mass. In a dog, the mass is usually a benign tumor, known as a hemangioma, or a malignant tumor, referred to as a hemangiosarcoma. Both tumors develop from the red pulp's blood vessels developing into a network of abnormal blood vessels, which eventually rupture and cause the spleen to bleed. Given the amount of blood the red pulp stores, the rupture can be life-threatening.
Symptoms of Spleen Tumors
Often the signs of a spleen tumor are difficult to detect because they're usually very subtle. The most obvious sign of a spleen tumor is a a distended abdomen, as the organ swells to accommodate its excess tissue. The dog may have a decreased appetite and associated weight loss. His gums and other mucous membranes may be pale and he may have an elevated heart and respiratory rate.
It's not unusual for a dog to show no signs of a splenic tumor until he collapses from the ruptured spleen. A dog who is suffering from a ruptured spleen will be suddenly weak and cold, with pale gums. If the spleen stops bleeding on its own, the dog will show remarkable improvement within a day, or even several hours later.
Spleen Tumor Risks
Some dog breeds carry a higher genetic risk of spleen tumors. English setters, German shepherds, Great Danes, boxers, pointers and golden retrievers have a higher incidence of splenic masses. Though younger dogs occasionally develop these tumors, the average age of occurrence is between 8 and 10 years. Male dogs tend to develop the tumors more than females.
If you suspect your dog may have a tumor in his spleen, it's vital to seek veterinary attention. Though the prognosis for hemangiosarcoma, the malignant tumor, is poor, the benign form of splenic tumor has a favorable prognosis if the spleen is removed. Generally, a splenectomy is the recommended course of action to avoid an urgent, life-threatening bleed-out, though applying a pressure bandage around his belly to buy time for veterinary treatment can be effective.