RADIOLOGY: VASCULAR: Case# 34: PULMONARY ARTERY ANEURYSM & THROMBOSIS. The patient is S/P left lobectomy in 1995 for a hilar mass. Pathology of the surgical specimen demonstrated caseating necrosis without evidence of malignancy. The patient was given the presumptive diagnosis of sarcoid and treated with Prednisone. The patient has had intermittent episodes of hemoptysis which has become acutely worse in the last three days. The patient also has right hilar mass noted on UAB chest radiograph in 07/96. The patient presents this morning with prominent hemoptysis. 1) Dilatation of the right pulmonary artery with abrupt cut-off of contrast enhancement with central hypodensity centrally and distally is consistent with pulmonary thrombus. Upon review of prior CT images dated 04/09/96, similar but smaller area of hypodensity within the right pulmonary artery was noted. Since this interval of time there has been marked enlargement of both the thrombus as well as the right pulmonary artery. Concentric thickening of the proximally opacified right pulmonary artery may be secondary to circumferential thrombus or intimal hyperplasia from long standing pulmonary thromboembolism. 2) Patchy air space disease within the lung bases may represent areas of aspirated pulmonary hemorrhage given the patients symptoms. Wedged shaped focal opacity in the right superior segment is suspicious for area of pulmonary infarct. 3) Low attenuation soft tissue density just anterior to the aortic arch is consistent with residual thymus. The appearance in size is unchanged compared to prior CT study performed at Medical Center East.