[Lung cancer occurring in a left upper division which is mirror imaged to a right upper lobe].

A 55-year-old man was admitted to our hospital because of an abnormal shadow in the left upper division on chest computed tomography(CT). Virtual bronchoscopy revealed a displaced anomalous bronchus. Thin sliced CT revealed complete lobulation between the upper division and the lingula. Three dimensional (3D)-CT revealed abnormal distribution of the left pulmonary artery which descended without passing over the left main bronchus. The left upper division was evaluated to be mirror imaged to a right upper lobe. Video assisted thoracoscopic left upper divisionectomy was performed. The tumor was diagnosed as adenocarcinoma( pT1aN0M0:p-stage I A).