True Tracheal Bronchus.

Area of Science:

• Thoracic Imaging
• Congenital Pulmonary Anomalies
• Bronchial Anatomy

Background:

• A 35-year-old male presented with chest pain and cough, leading to the discovery of a left hilar mass.
• Initial imaging revealed a mass involving the left main bronchus.
• A rare congenital bronchial anomaly was incidentally identified during the diagnostic workup.

Purpose of the Study:

• To report the incidental finding of a tracheal bronchus during the investigation of a hilar mass.
• To describe the anatomical characteristics of this rare congenital anomaly.
• To highlight the importance of recognizing incidental findings in thoracic imaging.

Main Methods:

• Chest radiography and computed tomography (CT) of the chest were performed.
• Multiplanar reconstruction of CT images was utilized for detailed anatomical assessment.
• Flexible bronchoscopy was conducted for biopsy of the hilar mass and direct visualization of the airway.

Main Results:

• A left hilar mass encasing the left main bronchus was identified.
• An incidental finding of a right-sided tracheal bronchus (also termed "pig bronchus" or "bronchus suis") was noted.
• Bronchoscopy confirmed an accessory bronchial opening supplying the right upper lobe, originating from the trachea.

Conclusions:

• The tracheal bronchus is a rare congenital variation in bronchial anatomy.
• Incidental identification of such anomalies during imaging for other pathologies is crucial.
• Awareness of the "pig bronchus" is important for accurate interpretation of thoracic imaging and airway assessment.