The tumor measures 1.8 cm in size and is completely surrounded by lung. This finding is felt to be secondary to the desmoplastic reaction incited by the tumor. There is retraction of the visceral pleura towards the lesion, and a small quantity of fluid collects within the space formed between the visceral and parietal pleura producing the finding identified on computed tomography. The finding does not indicate visceral pleural invasion. This large squamous cell carcinoma measures 5.4 cm in transverse dimension.
Linear densities radiate to the pleural surface from the lesion.
This finding is likely due to the desmoplastic reaction incited by the tumor. As previously discussed, retraction of the visceral pleura towards the lesion permits the development of a potential space between the visceral and parietal pleura. A small quantity of fluid within the space can produce a soft-tissue opacity between the lesion and the pleural surface. There is left upper lobe collapse which has caused the left mainstem bronchus to assume a more horizontal course. The atelectasis extends to the hilar region, but does not involve the entire left lung.