Mesotheliomas are uncommon tumors originating from the epithelial lining of the body’s cavities and internal structures. This lining, known as the mesothelium, is a membranous epithelial layer derived from the mesoderm cell layer. Its primary functions include lining the body cavity, protecting internal organs, and facilitating movement within the coelom (body cavity).
These tumors develop due to abnormal division and replication of mesothelial cells, leading to their migration to various sites in the body. Mesotheliomas can occur in the thoracic cavity, abdominal cavity, pericardial sac surrounding the heart, and in the scrotum of male dogs. As a result, affected dogs may experience displacement of internal organs, leading to gastrointestinal or cardiac symptoms. Mesotheliomas also tend to produce excessive fluid, making microscopic examination of fluid samples an essential diagnostic tool. Among dog breeds, German shepherds are the most commonly affected by mesotheliomas.
Symptoms and Types
- Difficulty breathing
- Dull heart, lung, and abdominal (ventral) sounds
- Swelling and enlargement of the abdomen due to fluid build-up
- Enlarged scrotum
- Intolerance to exercise
- Fatigue
- Vomiting
Causes
Exposure to asbestos is a recognized cause of mesothelioma development.
Diagnosis
Your veterinarian will conduct a comprehensive physical examination of your dog, considering its medical history, onset of symptoms, and any potential triggering incidents. A thorough blood analysis will include a chemical profile, complete blood count, and urinalysis. X-rays of the chest and abdomen will be crucial in confirming mesothelioma. Radiographs and ultrasound imaging may also reveal effusion or masses in the body cavities and pericardial sac.
Fluid samples will be collected for cytologic examination. In some cases, exploratory surgery or laparoscopy may be necessary to remove mesothelial masses for further laboratory analysis.
Treatment
Most pets can receive outpatient treatment. If your dog experiences difficulty breathing, it should be provided with a quiet resting place, away from activity and any exertion. Hospitalization may be necessary if your dog has excess fluid in its body cavities due to mesothelioma, such as in the chest or abdomen, to drain these cavities. Surgery may be required to relieve pressure if fluid accumulates in the pericardial sac.
Living and Management
During your dog’s recovery from mesothelioma, it’s crucial to limit its activity until breathing becomes easier. Stick to slow walks around the neighborhood and gentle playtime at home until your dog shows signs of improvement. Create a safe and calm environment for your pet, away from energetic children and other animals.
If cisplatin chemotherapy is part of your dog’s treatment plan, stay vigilant about monitoring its kidney health as some dogs may react adversely to the medication. Regular follow-up visits with your veterinarian are necessary for assessing kidney function and checking for any signs of metastasis in the chest and pleural cavity through X-ray imaging.