Echocardiographic, thoracic ultrasonographic, and CTA diagnosis of pericardial neoplasia in a dog.

A 12-year-old male neutered Yorkshire Terrier presented for coughing and respiratory distress. Transthoracic echocardiography initially misdiagnosed the patient with pericardial effusion; repeat echocardiography increased suspicion for neoplasia. A definitive diagnosis was not apparent. Findings on thoracic computed tomography and thoracic ultrasound were consistent with a diffusely thickened, heterogenous, hypoechoic soft tissue structure surrounding the heart. Fine needle aspirates were obtained using ultrasound guidance and routine cytology of the intrapericardial mass was consistent with neoplasia, with pericardial mesothelioma most likely. These novel findings highlight the importance of thoracic ultrasound and potential limitations of echocardiography in diagnosis of pericardial neoplasia.