A 34 year-old male was admitted after an episode of syncope. An echocardiogram revealed moderate enlargement of the RA and RV and an estimated systolic PA pressure of 85 mm Hg. A perfusion scan showed segmental perfusion defects in the RUL, RML and LLL. He underwent pulmonary thromboendarterectomy with removal of chronic and partially organized thrombus from all lobar and segmental vessels of the right lung, lingula and left lower lobe. Organized thrombus with some fresh clot is shown.