Findings:
There is a large mass that occupies the left hilum and extends into the subcarinal, right hilar, paratracheal regions bilaterally and the aortopulmonary window. The mass also extends anteriorly to reach the chest wall at the level of the second rib and costal cartilage. The mass does not contain any areas of calcification or necrosis. The pulmonary arteries traversing the large left hilar mass are narrowed. In particular contrast within the lingula artery is obliterated within the mass. The trachea, right and left main bronchus and the left upper and lower lobe bronchi remain patent.
There is suboptimal opacification of the pulmonary arterial circulation. Allowing for this limitation, no filling defect identified to suggest a pulmonary embolus.
Bilateral centrilobular emphysematous changes more prominent on the right. Thick linear bands of consolidation extend from the left hilum out to the pleural margins in both the left upper and lower lobes. The segmental bronchi supplying these regions of lung appear compressed by the hilar mass. Furthermore there is evidence of volume loss within the left hemithorax with elevation of the left hemidiaphragm. There are dilated interlobular septa most prominent within the apex of the left lung. Small region of scarring adjacent to the azygo-oesophageal recess. There is a 7 mm subpleural nodule within the right lower lobe. Bilateral fine dependent opacities most likely represent dependent lung change. No pleural effusions.
Within segment 4A/8 of the liver, there is a 21 mm subcapsular hypodensity. No suspicious bony lesion.
Conclusion:
There is a large infiltrative mass that occupies the left hilum and extends throughout the mediastinum. It surrounds and appears to occlude segmental airways of both the left upper and lower lobes, with focal regions of collapse within both the left upper and lower lobes and concomitant volume loss within the left hemithorax. The differential for this mass includes a primary lung malignancy or lymphoma.
Suboptimal contrast opacification of the pulmonary arterial system. Allowing for this, no pulmonary embolus identified. However the lingula segmental artery is compressed within the mass.
Interlobular septal thickening that appears to extend from the hilar mass into the left upper lobe is concerning for lymphatic extension of the mass.