This PA chest radiograph demonstrates an abnormal contour in the right hilar region, with visualization of the pulmonary vessels through the mass (the hilar<unk>  sign) indicating its posterior mediastinal location. On resection this was found to be a benign solitary fibrous tumor of the pleura. The<unk>  is an imaging appearance on chest radiographs in which the outline of the<unk>  can be seen at the level of a mass or collection in the mid chest. It implies that the mass is not in the middle mediastinum, and is either from anterior or posterior mediastinum(most of the masses arise from the anterior mediastinum).
Hilum overlay sign
Fat pad sign
Tree-in-bud sign
Air crescent sign
Companion shadow
Juxtaphrenic peak sign
Grey Turner's sign
Matchbox sign