Radiation Fibrosis : Differentiation from True Hilar Mass on Plain Chest Film

ABSTRACT

PURPOSE: Radiation-induced fibrotic mass might masquerade as a true hilar tumor mass on a plain chest radiograph. We attempted to differentiate radiation fibrosis from a true hilar tumor using only a plain radiograph. MATERIALS AND METHODS: Plain chest radiographs were obtained from seven patients who had developed radiation fibrosis simulating hilar mass after radiation therapy for lung cancer, and from 19 patients with lung cancer, a comparison group, who had not received radiation therapy. They were reviewed for the obliteration of the overlapped mediastinal and hilar anatomical silhouettes by the mass pulmonary artery, heart or aorta border, and paraspinal line. RESULTS: All seven patients with radiation-induced fibrotic mass(bilateral lesion in twopatients) showed obliteration of all three overlapped anatomical silhouettes of the mediastinum and hilum on chestradiographs. in the comparison group of 19 patients with a true hilar mass, there was, however, no case which demonstrated obliteration of all landmarks. CONCLUSION: Obliteration of all anatomical landmarks at the hilum and mediastinum may be a helpful clue in the differential diagnosis of radiation-induced fibrotic mass from true hilarmass on a plain radiograph, particularly when clinical information on previous radiation therapy is unavailable.