Fig. 9.

The major fissure mimicking pneumothorax on a radiograph in a 71-year-old man. He underwent partial resection of the right S6 for lung metastasis of esophageal cancer. a The major fissure appears as a thick linear opacity (black arrows) in the right lung field on a supine radiograph. It resembles the visceral pleura in pneumothorax. Unlike pneumothorax, vascular markings (black arrowhead) are visible outside of the thickened fissure. b An axial CT image shows the major fissure extending in the anteroposterior direction with a slight oblique angle (black arrows). Some volume loss in the right lower lobe caused the fissure to be displaced posteriorly; therefore, it seems to be visible on the anteroposterior radiograph