Tubular Narrowing of Pulmonary Artery Branches by Mediastinal Mass

A 42-year old woman presented with dyspnea on exertion, exertional chest pain NYHA functional class II, weight loss, and anorexia since 2 months ago. Physical examinations were in favor of tamponade, documented by emergent echocardiography; therefore, open drainage of pericardial fluid was done. After that, transthoracic echocardiography showed moderate right ventricular enlargement with mild systolic dysfunction. Also, there were mild tricuspid regurgitations with 57 mmHg gradient and turbulent flow Pulmonary Artery (PA) bifurcation, extended to its branches. Left ventricle size and function were normal. In transesophageal echocardiography, PA branches were concentrically narrowed from the origin to distal part (6 millimeters in diameter) with turbulent flow probably due to external compression of the surrounding mass (Figure 1A, Video1-6 (To see the videos, refer to the html Version)). PA CT angiography showed no sign of thromboemboli and amorphous low density mediastinal soft tissue surrounding narrow PA branches (Figure 1B). Besides, tuberculin test was negative. What was the diagnosis in transesophageal echocardiography and PA CT angiography?