A<unk>  is a segment of bronchus that is filled with mucus and completely enclosed so the mucus cannot drain out. This segment is usually dilated. It is also called bronchial mucocele. If there is no obstruction to the flow of mucus, it is called mucoid impaction of bronchus.<unk>  results from obstruction of bronchus. Overproduction of mucus can also contribute. Obstruction could be from scarring, tumor, congenital atresia, etc.
Bronchocele
Lung hernia
Peritonsillar abscess
Bronchogenic cyst
Tracheal tumor
Tracheoinnominate fistula
Bronchomalacia
Bronchopleural fistula