Pericardial mesothelioma with severe congestive heart failure in a Holstein cow

A 58-month-old Holstein cow showed anorexia, edema of the lower jaw and dewlap, jugular venous engorgement, abdominal gas, and watery diarrhea. Heart sounds were faint on auscultation, and decreased rumen motility was noted in physical examination. Echocardiography findings included adhesion of fibrin-like structures to the pericardium, highly echogenic periaortic region, and pericardial effusion, which suggested traumatic pericarditis or tumor formation. Although atypical mesothelial cells were observed in bloody pericardial fluid, no diagnosis was made. At complete necropsy, milky mass formation was observed on the epicardium. Histopathological examination led to a diagnosis of primary malignant pericardial mesothelioma. © 2017, Hokkaido University. All rights reserved