Tracheobronchomegaly

Imaging description Tracheobronchomegaly (Mounier-Kuhn syndrome) is characterized by dilatation of the intrathoracic trachea and mainstem bronchi [1–3]. Bronchiectasis involving segmental and subsegmental bronchi may also be present (Figures 5.1 and 5.2). Hyperinflation and/or emphysematous changes in the lung distal to the bronchial dilatation can also be seen (Figure 5.1). Tracheobronchomegaly is characterized by severe atrophy or absence of longitudinal elastic fibers and thinning of the muscularis mucosa within the wall of the trachea and central bronchi. This allows the membranous and cartilaginous portion of the trachea and mainstem bronchi to dilate. Redundant tissue between the cartilaginous rings develops and results in broad protrusions between the cartilaginous rings which can give the wall of the trachea a corrugated appearance (Figure 5.1). Importance Tracheobronchomegaly is likely an under-recognized disease as the majority of patients with this abnormality are asymptomatic. This is likely a congenital abnormality that is inherited as an autosomal recessive trait. There is striking male predominance although tracheobronchomegaly has been reported in women.