Idiopathic fibrosing mediastinitis is a rare entity involving more severely the more compliant structures within the mediastinum. In this report a rare case of simultaneous involvement of both the superior vena cava (SVC) and pulmonary veins is described in a 16--year old male with progressive dyspnea on exertion, cough and a three months' history of blood--tinged sputum. Physical examination and imaging studies revealed signs of pulmonary venous hypertension (PVH) and SVC stenosis. Fibrosing mediastinitis was confirmed by multiple biopsy samples.