Pathologically, there is loss of cartilage and muscle within the
trachea and bronchi, resulting in dilatation. Because of the loss of
inherent tracheal wall support, diverticula develop, commonly
posteriorly.2The inciting factor, however, is not known.
Some authors have speculated that the disease is congenital in nature
(a dysplasia), sometimes associated with Ehlers-Danlos syndrome in
adults and cutis laxa in children.3It has also been
associated with double carina, tracheal trifurcation, and a
congenitally short right upper lobe bronchus. Interestingly, there is a
return to normal bronchial size at the fourth or fifth bronchial
generation.4Others have suggested an acquired origin of
the disease, noting that almost 50% of patients show no symptoms until
the third decade of life.5 This might be in association
with cigarette smoking, although causation has not been studied. A rare
variant of the disease demonstrates an autosomal recessive pattern of
inheritance. The majority of patients are men.