A 32-year-old woman presented with cough and hemoptysis. The radiologic findings showed increased interstitial markings in the right lung, a slightly decreased lung volume in the RLL and a hypoplastic right pulmonary artery with collaterals in the mediastinum and subpleural area. The pulmonary angiography showed an abrupt occlusion of the right lower pulmonary artery. The echocardiographic findings indicated pulmonary hypertension. A doppler leg ultrasonograph disclosed that the left popliteal vein was occluded with collateral veins, not filling the defect in the venous lumen. The D-dimer increased 1.0 ug/ml. This condition was initially misdiagnosed as a congenital pulmonary artery agenesis. Finally, a chronic pulmonary thromboembolism with a deep vein thrombosis was confirmed.