Pericardial mesothelioma is a rare form of cancer that affects the pericardium, which is the sac surrounding the heart. It is commonly seen in humans, but it can also occur in animals, including cats. The diagnosis of pericardial mesothelioma in cats can be challenging due to its nonspecific clinical signs and lack of specific diagnostic tests. However, with a combination of imaging studies, cytology, and histopathology, pericardial mesothelioma in cats can be diagnosed with reasonable accuracy.
Clinical Signs
The clinical signs of pericardial mesothelioma in cats are similar to those seen in other pericardial diseases and can be non-specific, including lethargy, weakness, exercise intolerance, anorexia, cough, dyspnea, and abnormal heart sounds. Some cats may also present with clinical signs suggestive of right-sided congestive heart failure, such as ascites, pleural effusion, and jugular distention. In some cases, sudden death may be the first sign of pericardial mesothelioma.
Imaging Studies
Chest radiography and echocardiography are the primary imaging modalities used to evaluate cats with suspected pericardial mesothelioma. Chest radiographs may reveal an enlarged cardiac silhouette, pleural effusion, and pulmonary infiltrates, but they lack sensitivity and specificity for pericardial mesothelioma. Echocardiography is essential in the diagnosis of pericardial effusion, which is a hallmark of pericardial mesothelioma in cats. It can also reveal the presence of pericardial masses, thickening, and calcifications, which are suggestive of pericardial mesothelioma.
Cytology
Pericardial effusion cytology is a minimally invasive method to diagnose pericardial mesothelioma in cats. It involves the aspiration of pericardial fluid using a fine needle and the examination of the fluid under a microscope. The presence of mesothelial cells, multinucleated giant cells, and marked atypia are suggestive of pericardial mesothelioma. However, false-negative results may occur due to inadequate sampling, and false-positive results may occur due to reactive mesothelial hyperplasia.
Histopathology
Histopathology is the gold standard for the diagnosis of pericardial mesothelioma in cats. It involves the surgical removal of pericardial masses or biopsies under general anesthesia. The histopathological examination of the tissue samples can confirm the diagnosis of pericardial mesothelioma by revealing the characteristic features of mesothelioma, such as spindle-shaped cells, tubulopapillary, or solid patterns, and invasion of adjacent tissues. Immunohistochemistry can also be used to differentiate pericardial mesothelioma from other pericardial tumors, such as hemangiosarcoma and lymphoma.
Conclusion
Pericardial mesothelioma is a rare but deadly disease in cats. The diagnosis of pericardial mesothelioma in cats can be challenging due to its nonspecific clinical signs and lack of specific diagnostic tests. However, with a combination of imaging studies, cytology, and histopathology, pericardial mesothelioma in cats can be diagnosed with reasonable accuracy. Early diagnosis and treatment can improve the prognosis and quality of life of affected cats.
