Objective Fetal hydrothorax may lead to hydrops and is associated with mortality as high as 50%. The objective of this study was to define the pathophysiology of fetal hydrothorax and its relation to hydrops. Methods

It has been described the anatomopathological and immunohistochemical characteristics of a multinodular neoplasm distributed in the parietal and visceral pleurae, pericardium, thoracic portion of the diaphragm and renal cortex of an eight year-old, female, mixed breed, cat. Based on the anatomopathological and immunohistochemical findings it was firmed the diagnosis of biphasic pleural mesotelioma with renal metastasis.