Abstract
A six year old Holstein cow was referred for clinical evaluation of lethargy and progressive bilateral abdominal distension of one month's duration. When first examined, the cow was lethargic, dehydrated and in a poor physical condition. Abdominal distension was prominent. Ultrasonographic examination of the right and left abdomen revealed a massive amount of hypoechogenic fluid in the abdominal cavity. It also revealed irregular cauliflower-like masses adherent to the abdominal wall in numerous locations, evidently fused to the peritoneum and characterized by mixed echogenicity. Ultrasonographic examination of the thorax revealed intra-pleural effusion and an irregular appearance of the pericardial surface. Ultrasonography proved to be a useful tool for early prediction and prognosis of mesothelioma in the cow; and to rule out other causes of non-inflammatory ascites. Ultrasonographic examination combined with ultrasound-guided fine-needle aspiration and biopsy yielded a definitive ante mortem diagnosis and helped in determining the prognosis of the case.