Extrinsic Pulmonary Artery Compression Mimicking Pulmonary Stenosis: A Case of Mediastinal Lymphoma

Abstract

Background: Pulmonary artery stenosis (PAS) is an uncommon cause of right ventricular pressure overload, most often congenital. Acquired PAS caused by extrinsic vascular compression is rare but can have serious hemodynamic consequences, including progressive right ventricular dysfunction and heart failure if not promptly diagnosed and well managed. Case Summary: A 37-year-old woman presented with progressive exertional dyspnea and signs of right heart failure. Transthoracic echocardiography showed moderate supravalvular pulmonary stenosis with severe tricuspid regurgitation and right heart dilation. Contrast-enhanced computed tomography (CT) revealed a large mediastino-pulmonary mass compressing the pulmonary artery and its branches. FDG-positron emission tomography scan demonstrated hypermetabolic activity of the mass and associated lymphadenopathy. CT-guided biopsy confirmed the diagnosis of lymphoma. The patient was admitted to the hematology-oncology department and was placed on chemotherapy. Discussion: This case underscores the importance of considering malignancy in the differential diagnosis of acquired pulmonary artery stenosis. Multimodal imaging is essential for accurate diagnosis and guiding management in patients presenting with unexplained right heart failure due to vascular compression.