The spleen is the storehouse of blood. It also functions as an organ for destroying old red blood cells and holding blood for emergencies. It is an important part of the body’s immune system. Located just below the stomach, it springs into action to provide blood for replenishing the loss in emergencies such as a hemorrhage. Even though life can be normal without a spleen, its absence predisposes dogs to infections.
The spleen constitutes of a red soft surface containing two different types of pulp - white and red. While the red pulp functions as a mechanical filter removing unwanted substances from the blood, the white pulp helps to fight infections.
A growth in the spleen signifies an abnormality, and the presence of cancer cells needs to be investigated. A growth leading from the red pulp is usually a rare malignant neoplasm characterized by rapidly proliferating anaplastic cells known as hemagiosarcoma. It is derived from blood vessels lining blood-filled spaces. Growths arising from the white pulp are either mast cell tumors or a lymposarcoma, which is the more common type of feline cancer rather than canine cancer. Two thirds of all spleen tumors signify cancer in dogs. Again about two thirds of all malignancy in the spleen arises from the red pulp causing hemagiosarcoma.
Some splenic tumors can look exceptionally large in radiographs but may actually turn out to be benign. Even benign tumors can be very dangerous as they can rupture any moment without notice, often resulting in instant death due to excessive bleeding. A ruptured tumor necessitates immediate attention, a quick diagnosis, surgery and intensive care.
Clinical signs of a splenic tumor can be as confusing as the symptoms of liver cancer in dogs. Your dog may show pale gums, and a distended stomach or a hard mass in the abdomen. Some general symptoms like weakness and loss of appetite also indicate a splenic tumor. One of the prominent signs is the change in color of the urine due to breakdown of red blood cells when hemoglobin starts getting excreted. The urine may develop a dark brown color.
Prognosis of a benign tumor is good, and surgery is an effective treatment. In some cases, there are only torsions, or twists of the spleen, which too have a good prognosis. If malignancy is not suspected, the dog may require to be stabilized with intravenous fluids and a blood transfusion.
Malignancy, however, requires the spleen to be removed. After surgery, there may be complications like infection, death due to anesthesia, and an abnormal rate of muscle contractions in the heart that may even cause an instant death.
Splenic tumors often tend to metastasize to the lungs, liver, heart and other organs of the body. Even a small malignant tumor in the spleen cannot be felt on palpating the abdomen. The only way a splenic tumor can be detected in its early stage is through regular check-ups.