A man in his 60s was referred to our department because he was suspected to have collagen disease-associated interstitial pneumonia. Computed tomography showed the displaced right B3 bronchus bifurcating from the right middle lobe bronchus, the right A3 bifurcated from a more distal position of main pulmonary artery compared to B1+2, and there was no fissure between the right upper and middle lobes. Bronchoscopy confirmed that the B3 bifurcated from the proximal side of the middle lobe bronchus. Cases of displacement of the right B3 bronchus bifurcating from the right middle lobe bronchus have abnormalities of pulmonary artery branching and lung lobulation. It would be needed to combine findings from multiple examinations for the diagnosis of a displaced bronchus.

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