Isolated left hypoplasia of the pulmonary artery accompanied by lung hypoplasia and chronic bronchial disease in a cat.

A 2-year-old castrated Russian Blue cat presented with inappetence, depression, and labored respirations. Radiography findings suggested left lung atelectasis; however, the ultrasonography findings did not indicate lung atelectasis. The left pulmonary artery (PA) was abnormally small on echocardiography; further, there were no other cardiac anomalies. Computed tomography revealed an abnormally small left PA and left lung. Furthermore, bronchiectasis and tree-in-bud patterns were observed in the lung lobes. Based on these findings, the cat was diagnosed with isolated left PA hypoplasia, presumed left lung hypoplasia, and feline chronic bronchial disease. Early diagnosis of this disease is important because it can cause serious complications, including recurrent respiratory infection, bronchiectasis, massive hemoptysis, and pulmonary hypertension.