Tracheal Bronchus

Axial and coronal-reformatted CT images in a patient with tuberculosis of the right upper lobe (stars) show a tracheal bronchus (arrows) arising from the right lateral wall of the trachea, within 2 cm of the carina. Note a normal-appearing right upper lobe bronchus (arrowhead). 

Facts

• Abnormal bronchus arising directly from the lateral wall of the trachea (on either side, but right side is more common), supplying the upper lobes
• 0.1% - 2% incidence
• Most cases are found incidentally on bronchoscopy or CT
• Associated with other anomalies such as ribs, vertebrae

Types

• Two types: displaced, or supernumerary
• "Displaced" type = RUL bronchus or any of its segmental bronchus in cephalad location than normal. If the entire RUL bronchus arises from tracheal wall, it is called "bronchus suis"
• "Supernumerary" type = normal RUL bronchus and its segmental bronchi but there is extra bronchus arising directly off the lateral wall of the trachea

Clinical implications

• In children, it is associated with recurrent infections, stridor, respiratory distress and thoracic masses
• In adults, it can complicate endotracheal intubation (occlusion or accidental intubation of a tracheal bronchus can cause atelectasis)

Our case: supernumerary bronchus arising from the right lateral wall of the trachea. The patient presented with TB of the right upper lobe. 

Reference:

Aoun NY, et al. Tracheal bronchus. Respir Care 2004;49:1056-8.