Coelomic and Pericardial Effusion Associated with Mesothelioma in a Savannah Monitor (Varanus exanthematicus)

Abstract

An adult male Savannah monitor (Varanus exanthematicus) was evaluated for lethargy, anorexia, and coelomic distension. Ultrasonographic investigation identified both pericardial and coelomic effusion. Clinical laboratory investigations and radiographs did not identify a definitive disease process, and culture of the coelomic fluid was negative for bacterial growth. A tentative diagnosis of neoplasia, with mesothelioma as a potential type, was made after cytological examination of the coelomic fluid and echocardiography. Surgical exploration and excisional biopsy of the pericardium for drainage of the fluid and determination of a final diagnosis was carried out. The lizard died 16 h post-anesthesia. Histopathology confirmed changes throughout the coelomic cavity consistent with a diagnosis of mesothelioma. Mesothelioma is a rarely reported neoplasm in all animals but particularly in reptiles. This case report provides a detailed clinical and pathologic description of the lesions associated with mesothelioma in a monitor lizard. In addition, this is the first known report of a surgical pericardectomy in a reptile.