Lymphomatoid granulomatosis is an extremely rare form of lung tumor that occurs in both dogs and humans. With this disease, abnormal cells from the lymphatic system enter the blood vessels serving the lungs. Because lymphomatoid granulomatosis is a form of cancer, these cells grow and multiply in the blood vessels, leading to the symptoms of the condition. Since no cure is available, veterinarians generally recommend using chemotherapy to slow the spread of the disease, or no treatment.
Sometimes referred to as pulmonary lymphomatoid granulomatosis or PLG, this rare disease is a form of lung cancer. Cancerous white blood cells, including lymphocytes and plasmocytes, begin entering the blood vessels, arteries and veins that service the lungs. The presence of these cells causes inflammation in the vessels that leads to the formation of granulomas, which are pieces of inflamed tissue. These granulomas interfere with the normal processes of the respiratory system. Additionally, these cancerous white blood cells can move to other parts of the body, including the liver and pancreas, to cause similar damage to those organs.
Dogs affected by pulmonary lymphomatoid granulomatosis can show a number of different symptoms. Unfortunately, these symptoms are also indicative of a wide range of health concerns, so their presence alone is not enough to determine that a canine has this form of cancer. Dry, nonproductive coughing and breathing difficulties are two important warning signs. Along with these primary symptoms, dogs may also lose weight and stop wanting to eat. They may also have nasal discharge and fever. Many animals also become inactive, usually as a result of their breathing difficulty.
Because the symptoms alone could be caused by a number of diseases, your veterinarian will need to perform lung X-rays and do blood work to look for signs of pulmonary lymphomatoid granulomatosis. In the X-rays, your veterinarian will be looking for dark or opaque spots in the lungs, which suggest the presence of the granulomas. The blood work in these cases will also reveal an abnormally high white blood cell count. Even then, your veterinarian may decide to remove a section of tissue from the lungs to study further. Once all of these tests are completed, the veterinarian can make a diagnosis and, if the dog does have PLG, can determine an appropriate treatment plan.
Since no cure is available for PLG, treatment usually focuses on removing the cancer from the body or slowing its growth. Veterinarians can use a combination of chemotherapy and surgery to eliminate the cancerous cells and inflamed tissue from the dog's body. Using chemotherapy on dogs can be dangerous to them, so the veterinarian and owner must decide whether the potential benefits outweigh the risks. Even with treatment, the cancer can spread to other parts of the dog's body. If this occurs, or if other complications arise from the treatment, the veterinarian may recommend ceasing treatment altogether.
- petMD: Cancerous Lymphoid Cells in the Lungs of Dogs
- Sage Journals/Veterinary Pathology: Pulmonary Lymphomatoid Granulomatosis in a Dog
- Sage Journals/Veterinary Pathology: A Lymphomatoid Granulomatosis of the Lungs in Young Dogs
- Medscape: Lymphomatoid Granulomatosis
- Mayo Clinic: Granuloma: What Does It Mean?
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