Clinical presentation:
Man aged 47yr with back pain and night sweats.

There is a low density area in the glenoid of the left scapula. It is irregular and not sharply defined. A more subtle zone of patchy loss of bone density lies in the posterior margin of the left 1st rib. The upper mediastinum is widened. There is a left-of-mid-line soft tissue density, which is separate from the soft tissue boundaries of the aortic arch and a left subclavian that is more prominent than usual. The centre of radius of the paraspinal density lies at the level of T4/T5 vertebrae. Posteriorly, the 4th and 5th ribs are more crowded than the 3rd and 4th ribs. On the right side, there are three soft-tissue curves. The upper two sharp soft tissue boundaries do not appear to extend behind the right clavicle. This loss of silhouette implies an anterior structure. The trachea is undistorted. The lowest curve has a centre of radius, related to the spine at roughly the level of 5th thoracic vertebra. It lies away from the right tracheo-bronchial angle and may not necessarily be azygous vein, despite its superficial resemblence.