CASE 2536 Published on 26.01.2004

Tracheal Bronchus

Section

Chest imaging

Case Type

Anatomy and Functional Imaging

Authors

Michailidis G, Kontopoulou Ch, Argentos S, Economopoulos N, Kelekis N

Patient

88 years, male

Categories
No Area of Interest ; Imaging Technique CT, CT
Clinical History
Fever of unknown origin. Previous history of tuberculosis in early adulthood.
Imaging Findings
The patient presented for investigation of fever of unknown origin. He had a history of tuberculosis in early adulthood.
CT scan of the chest was performed which revealed the incidental presence of a right tracheal bronchus arising just above the main carina and trifurcating into the segmental bronchi of the right upper lobe.
Discussion
Tracheal bronchus is a developmental abnormality of the airways. Its prevalence ranges from 0,1%-2% on the right side and 0,3%-1% on the left side in bronchoscopic examinations. A higher incidence has been noted however in children with Down’s syndrome.
Congenital anomalies that can be associated with a tracheal bronchus include tracheal stenosis, tracheoesophageal fistula, laryngeal web, rib and vertebra anomalies, congenital heart disease and VATER syndrome (vertebral defects, anal atresia, tracheoesophageal fistula, esophageal atresia, renal defects and radial dysplasia).
There are two types of tracheal bronchus, the displaced type and the supernumerary type. In the first type either the apical (apicoposterior on the left side) segmental bronchus only or all segmental bronchi of the upper lobe arise from the tracheal bronchus. In the second type there is a normal upper lobe bronchus arising from the main carina in addition to the tracheal bronchus. The first type is more frequent.
CT scans of the chest demonstrate an abnormal bronchus arising from the right lateral wall of the trachea usually up to 2cm above the carina. Identification of this anomaly is easier using high-resolution spiral CT protocols and coronal imaging, which can additionally help differentiate a displaced from a supernumerary bronchus. In case of a supernumerary bronchus it can be either ending blindly (tracheal diverticula) or supplying a segment of the lung (tracheal lobe).
In most cases this abnormality is clinically insignificant and represents an incidental finding. However under certain circumstances (e.g. intubated patients) it can be potentially dangerous. Common complications, as a result of insufficient drainage of the involved bronchi, include recurrent infections, chronic atelectasis, chronic bronchitis and bronchiectasis. Despite being generally a clinically insignificant abnormality, it should be considered especially in intubated patients with persistent atelectasis, as this can represent a complication due to obstruction of the tracheal bronchus’ orifice. Early detection is important.
Differential Diagnosis List
Tracheal Bronchus
Final Diagnosis
Tracheal Bronchus
Case information
URL: https://www.eurorad.org/case/2536
DOI: 10.1594/EURORAD/CASE.2536
ISSN: 1563-4086