Unilateral Left Pulmonary Edema Caused by Contained Rupture of the Ascending Aortic Dissection

Unilateral pulmonary edema (UPE) is a rare entity and is usually associated with severe mitral regurgitation and more frequently occurs in the right lung. We herein report a case of unilateral left pulmonary edema caused by external compression of the right pulmonary artery and left pulmonary vein caused by the presence of hematoma due to type A acute aortic dissection (AAD), resulting in asymmetrically increased inflow and decreased outflow in the left pulmonary circulation. Physicians caring for patients with UPE should be aware that AAD leading to the external compression of the heart may be a possible underlying mechanism.