Introduction
The result is space occupying disease and depending on the location and degree of structural change symptomatology clinical and radiological findings will differ. Partial obstruction may cause focal emphysema while a total obstruction may lead to segmental or subsegmental atelectasis. Secondary infection may result in bronchitic, pneumonic change and even abscess formation
Venous structures can also be compressed the most dramatic of which is the involvement of the SVC and resulting SVC syndrome.