Tracheal trifurcation: new cases and review of the literature.

Tracheal trifurcation is an uncommon and often unknown type of anomalous tracheobronchial arborization, characterized by three main bronchi originating at the level of the carina. Diagnosis is important due to its clinical implications. To highlight the anatomical, clinical and diagnostic aspects of tracheal trifurcation by reporting our experience and reviewing the literature. We retrospectively evaluated pediatric patients referred to our institution from January 2018 to May 2020 with a diagnosis of tracheal trifurcation. All patients underwent chest radiographs, computed tomography (CT) (with/without dynamic airway scanning) and bronchoscopy. Clinical and anatomical data were collected. Three patients with tracheal trifurcation were identified (1 female, median age: 7.6±0.4 months). All had associated anomalies: two had tetralogy of Fallot, one with esophageal atresia/tracheoesophageal fistula and one with an atrioventricular septal defect, and the other had skeletal ciliopathy. Chest radiographs were not diagnostic for tracheal trifurcation. Bronchoscopy could not fully evaluate the trachea and main bronchi in two cases. CT detected tracheal trifurcation in all of the patients and also demonstrated other lung parenchymal and congenital anomalies. Two of the three main bronchi were directed to the right lung in all cases. Ostial stenosis of either the central (two patients) or right upper bronchus (one patient) was present. No signs of tracheobronchomalacia were found. Tracheal trifurcation is rare and often associated with additional disorders, such as other tracheobronchial anomalies, cardiovascular defects or esophageal malformations, responsible for clinical manifestations and earlier detection. Bronchoscopy is often used for diagnosis, but is invasive and may be incomplete or inconclusive, while CT allows for a noninvasive and correct diagnosis, while also highlighting additional findings in the thorax.