Computed Tomography in Pulmonary Artery Sarcoma

OBJECTIVE: The purpose of this study was to present the computed tomography (CT) findings of pulmonary artery sarcoma in 7 patients with a focus on the distinguishing features of pulmonary embolic disease. METHODS: For the 9 years from December 1993 to November 2002, we treated 7 patients with pathologically proven pulmonary artery sarcoma, and during the 2 years from December 2000 to November 2002, we treated 40 patients with acute (n = 33) or chronic (n = 7) pulmonary embolism. In these patients, pulmonary embolism was diagnosed from serial CT or clinical findings. Two chest radiologists, blinded to the diagnoses, independently reviewed the scans of all 47 patients in random order, and the so-documented CT features of sarcoma and pulmonary embolism were compared by using Fisher exact test or the generalized estimating equations test. RESULTS: The two most frequent CT findings of pulmonary artery sarcomas were a low-attenuation filling defect occupying the entire luminal diameter of the main (n = 1) or proximal (n = 6) pulmonary artery and an expansion of any segment of the pulmonary artery with extensive intraluminal filling defect, as observed in six (86%) of 7 patients. In contrast, the finding of a lesion occupying the entire luminal diameter at the level of proximal pulmonary arteries was absent in all 40 patients with pulmonary embolism (P < 0.0001) (kappa = 0.9111). Expansion of the pulmonary arteries was seen in one (3%) of 40 patients with pulmonary embolism (P < 0.0001) (kappa = 0.9108). Extraluminal extension was observed in 5 of 7 (71%) patients with sarcoma, but in no patient with an embolism (P < 0.0001) (kappa = 0.8773). CONCLUSION: CT can help differentiate pulmonary artery sarcoma from pulmonary embolism by indicating a low-attenuation filling defect occupying the entire luminal diameter of the proximal or main pulmonary artery, expansion of the involved arteries, or extraluminal tumor extension.