Pulmonary vein stenosis secondary to a mediastinal mass in a cat.

This report describes the case of a 5-year-old spayed female munchkin cat that was presented with respiratory distress. Thoracic radiography revealed pleural effusion with a diffuse interstitial lung pattern. Echocardiography identified a mass compressing the left atrium, accompanied by a turbulent jet-like flow from the pulmonary veins, with a velocity of 1.6 m/s. Computed tomography revealed a diffuse, homogenous mediastinal mass compressing the dorsal border of the left atrium and surrounding the ascending aorta and the pulmonary arteries and veins. The distal caudal pulmonary veins were dilated, indicating pulmonary vein stenosis secondary to the mediastinal mass. The caudodorsal ostium was stenotic due to the mediastinal mass compression. In addition, bilateral adrenomegaly and multifocal masses were evident in the kidneys, stomach, and cecum. Lymphoma was diagnosed in the cecal mass using cytology and PCR for antigen receptor rearrangements (PARR). This case describes clinically significant acquired pulmonary vein stenosis secondary to a mediastinal mass, which was likely responsible for the respiratory distress and pleural effusion. Key clinical message: To our knowledge, this is the first report of acquired pulmonary vein stenosis secondary to a mediastinal mass in a cat. Computed tomography could be helpful in confirming pulmonary vein stenosis and identifying its etiology.