Heart Tumors in Cats

Hemangioma tumors are made up of new lymph or blood vessels, and they are generally harmless, as they do not spread throughout their body. Hemangiosarcoma tumors develop in the blood vessels of the heart and affect its ability to function properly. If left untreated, the tumors can spread to the liver, spleen, lungs and heart. This can lead to other health problems, collapse, and death.

Benign tumors that start in the heart valve tissues are known as fibromas. Fibrosarcoma is a tumor of the heart valve tissue that is not benign. Tumors of the upper heart chambers are known as myxomas when benign and myxosarcomas when malignant. Rhabdomyosarcoma is a malignant tumor that starts in the skeletal heart muscle.

Though rare, several types of heart tumors may develop in cats. Tumors are generally classified by their location or makeup.

Symptoms may vary depending on where the tumors are located, and usually appear when the tumor has ruptured. You may notice the following symptoms of heart tumors:

• Coughing
• Lethargy
• Shortness of breath
• Irregular heartbeat
• Heart murmurs
• Loss of appetite
• Loss of weight
• Fluid in abdomen
• Collapse

If you notice any signs of heart tumors, take your cat to the veterinarian immediately. The symptoms could be a sign that the tumor has started to rupture and bleed.

Types

There are several types of tumors that occur near or within the heart:

• Hemangioma: Benign tumors made up of lymph or blood vessels that have just formed.
• Hemangiosarcoma: Malignant tumors that start in the blood vessels of the heart.
• Fibroma and fibrosarcoma: Develop in the heart valve tissues.
• Myxomas and myxosarcomas: Develop in the upper heart chambers.
• Rhabdomyosarcoma: Malignant tumor of the skeletal muscle of the heart.

Secondary tumors that can spread to the heart are as follow:

• Lymphomas: Tumors of the lymph nodes, which are malignant.
• Osteosarcomas: Tumors of the bone, which are also malignant.
• Neurofibromas: Tumors of the nerve fibers, which are benign.
• Granular cell tumors: It is unknown where these benign or malignant tumors develop.

The cause of heart tumors in cats is not completely known by veterinarians. The tumors can come on unexpectedly and develop in any area of the body. There are also tumors that start in another part of the body and spread to the heart, such as lymphomas, neurofibromas, and granular cell tumors. 

Your veterinarian will give your cat a physical exam and ask questions about its medical history. Expect your veterinarian to run additional tests to check for benign or malignant tumors and see if they have spread throughout the body. The tests include a complete blood count, platelet numbers, chemical blood profile and a urinalysis.

Chest x-rays and an echocardiography may be performed to look for tumors and check that the heart is functioning properly. Your veterinarian will use an electrocardiogram to evaluate the electrical currents of the heart. Abdominal x-rays are performed to check for tumors and other problems in the stomach, intestines and spleen. 

Your cat may also need to undergo an abdominal tap, pericardial tap and clotting test. There is a chance your veterinarian will need to perform a biopsy by surgically removing a sample of the tumor.

It is important to have the heart tumor diagnosed and treated before it becomes fatal for your cat.

Surgery is recommended for most types of heart tumors in cats. The prognosis depends on the severity of the tumor and whether or not it has spread throughout the body.

Treatment of a Benign Tumor

Surgical removal is the best option for a benign tumor, and the prognosis following the surgery is usually good.

Treatment of a Malignant Tumor

Your veterinarian may recommend chemotherapy and surgery to reduce the growth and spread of the tumor. The tumor can be removed if it is small and has not spread throughout the body. If the tumor has already grown and spread throughout the body, then the prognosis is usually poor.

Whether heart tumors are benign or malignant, follow up appointments are an important part of the recovery process. Your veterinarian will check to see if the tumors are still growing or spreading. They will also make sure your cat is not having a negative reaction to the treatment. Your veterinarian will also give you the final prognosis, which depends on the severity of the tumors.

It is important to follow the instructions from your veterinarian despite the prognosis. The goal is to keep your cat comfortable throughout its lifespan.