A rare case of a bronchial anomaly running in the hilar region from the right lower lobe to the middle lobe.

A 77-year-old male was referred to our department due to lung cancer (cT3N0M0) of the right lower lobe. During right lower lobectomy, a thin duct structure was recognized in the hilar region between the middle and lower lobes that was identified to be a supernumerary bronchus upon a review of the preoperative chest CT images. Although bronchial anomalies are rare, it is important to carefully view preoperative images for any such anomalies in order to more safely perform surgery.