PLEUROPERITONEAL PAPILLARY EPITHELIOID MALIGNANT MESOTHELIOMA IN A NELLORE COW: CASE REPORT

Abstract

Mesothelioma is a malignant neoplasm of mesothelial cells. Being considered rare in domestic animals, it has a higher prevalence in cattle and dogs, regardless of sex. Affects, most commonly, the pleura and the peritoneum, however, the pericardium and testicular tunica are eventually also affected. The objective is to report the clinical care and necropsy of an adult cow, Nelore breed, diagnosed with papilliform epithelioid mesothelioma. The animal was treated on a property located in the countryside of Toledo, Paraná, with the history of progressive weight loss and increased abdominal circumference for three months. Physical examination showed paled mucous membranes, dyspnea and low body condition score. The diagnosis was confirmed through necropsy and histopathological examination, which showed the presence of numerous multifocal, whitish, firm and irregular neoformation, of different sizes, disseminated all over the entire parietal peritoneum and the serous surfaces of various organs, in addition to large amount of free fluid in the abdominal cavity. Fragments of the neoformations were collected and submitted to histopathological examination, which revealed the presence of neoplastic proliferations of epithelial cells, with polygonal to round shape, broad and eosinophilic cytoplasm, round and eccentric nucleus with loose chromatin and presence of mitotic figures. Due to these findings, the diagnosis of papilliform epithelioid pleuroperitoneal mesothelioma was established.