Pleural tags refer to slender bridges of soft tissue seen on CT scans that extend between masses in the lungs and the pleura.
They result from interlobular septal thickening of the lung. These septae may be distorted and reoriented or maybe normal in course. The septae are however abnormally thickened which can occur from a number of processes
- localised oedema (possibly related to lymphatic obstruction)
- tumour extension within or outside of lymphatic vessels
- inflammatory cells
The associated fibrosis can be either the desmoplastic reaction caused by a neoplasm or associated with an inflammatory response to benign disease.
There is development of overlying puckering to the pleural surface due to anatomic continuation between septae and the visceral pleura.
They have sometimes been classified into three types
- type 1: one or more linear pleural tag
- type 2: one or more linear pleural tag with soft tissue component at the pleural end
- type 3: one or more soft tissue cord-like pleural tag
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