Figure 7. 46-year-old man with right upper lobe atelectasis due to adenocarcinoma arising from the right upper lobe bronchus. (a) Posteroanterior radiograph shows a large opacity with a sharp lateral margin. Since the trachea is slightly displaced to the left, a mediastinal mass may be considered. Note elevation of the right hemidiaphragm. (b) CT demonstrates the atelectatic right upper lobe adjacent to the mediastinum. The right main bronchus is stenotic due to tumour invasion.