Peripheral pulmonary arterial stenosis due to lung tumor in a cat

A four-year-old castrated male American shorthair cat presented with lethargy, anorexia, and tachypnea. Echocardiography revealed a large mass compressing both branch pulmonary arteries. An increased peak systolic flow velocity in the left pulmonary artery (3.2 m/sec; estimated peak pressure gradient, 41 mmHg) was consistent with peripheral pulmonary arterial stenosis. Pulmonary hypertension was suspected based on echocardiographic findings. Computed tomography angiography demonstrated bilateral pulmonary artery stenosis by a pulmonary mass, and fine-needle biopsy cytology was consistent with lung carcinoma. Because of advanced disease with bilateral pulmonary artery involvement and suspected distant metastases, interventional treatment was not performed. This is the first report of acquired peripheral pulmonary arterial stenosis secondary to pulmonary carcinoma in a cat.