1. Introduction
1) It was described by Sandifort in 1975 as a right upper bronchus originating in the trachea.
2) The term tracheal bronchus includes a variety of bronchial anomalies arising in the trachea or main bronchus and directed toward the upper-lobe territory.
3) This anomalous bronchus usually exits the right lateral wall of the trachea less than 2 cm above the major carina and can supply the entire upper lobe or its apical segment.
4) Tracheal bronchi occur almost exclusively on the right trachea and are associated with other congenital anomalies, particularly trisomy 21.
5) The defect in embryogenesis that results in this disorder is uncertain. Possible mechanisms include abnormalities in migration, selection, or reduction of airways during development.
6) In the embryonic stage, the respiratory system begins its development in the third week of gestation, and the main branches of the tracheobronchial tree down to the terminal bronchiol are completed at 16 weeks of intrauterine life.
7) Tracheobronchial anomalies (TBA) originate, during this period, mainly at the level of the right main bronchus.

2. Incidence
1) Tracheal bronchus is a common airway malformation, with an incidence of 0.1 to 5 percent.
2) The development of pediatric bronchoscopy in the last several years has allowed us to estabilish a better diagnosis of these anomalies.
3) Those incidence varies from 1-3% of total bronchoscopies.

3. Classification
Andrew etc. illustrate 3 types of tracheal bronchi: 1) vestigeal tracheal diverticulum (newly described), 2) high apical lobe, and 3) fully developed supranumeray aerated tracheal bronchus.
(Otolaryngol Head Neck Surg. 2002 Mar; 126(3):240-3.)

4. Clinical manifestations
1) Tracheal bronchus may be asymptomatic or the cause of recurrent infections due to retained secretions.
2) Strido, recurrent pneumonia, and suspected foreign body aspiration are commen presenting complaints in children ultimately diagnosed with tracheal bronchus.

5. Diagnosis
1) The diagnosis can be made with rigid and flexible bronchoscopy or with image studies.
2) Direct bronchoscopy provides a clear definitive view of the anomaly.
3) Flexible bronchoscopy is useful to document the presence of segmental bronchi within the tracheal broncus.

6. Treatment
1) Treatment is based on the severity of the symptoms.
2) Most patients with tracheal bronchus can be treated consevatively.
3) In the case of recurrent respiratory infections, the treatment of choice is resection of the anomalous lobe and bronchus.

7. Discussion
1) Tracheal bronchus should be included in the differential diagnosis of any child who presents with recurrent right lobe pneumonia or collapse, particularly in children with other congenital deformities.
2) Bronchoscopy with selected radiographic imaging allows to fully evaluate the child with a tracheal bronchus