左B1＋2気管支転位領域に発生した肺癌の1例

Left Upper Lobectomy for Lung Cancer Arising in a Displaced Anomalous Bronchus：Report of a Case

はじめに　過剰気管支と転位気管支に分類される気管支分岐異常はまれである．術前に3D-CTを用いて解剖学的異常を把握し，安全に手術を遂行することができた左B1＋2気管支転位領域に発生した原発性肺癌の1例を報告する．

A 69-year-old man was diagnosed with an abnormal shadow on a chest X-ray during a routine check-up. Computed tomography （CT） showed a 36 mm solid nodule at left S1＋2, and 3 dimentional （3D）-CT showed the left B1＋2 branching from the left main bronchus. Bronchoscopy showed branching of B1＋2, B3～5, and inferior lobar bronchus from the left main bronchus, and a biopsy from the peripheral area of B1＋2 confirmed the diagnosis of lung adenocarcinoma. Subsequently, video-assisted thoracoscopic surgery was performed for the lung adenocarcinoma （cT2aN0M0, ⅠB）. The dorsal pleura was incised and B1＋2, which branches from the left main bronchus dorsal to the pulmonary artery, was identified. After dissecting B1＋2, the fissure between the upper division and lower lobes was separated, followed by left upper lobectomy with ND2a-1. The preoperative understanding of the anatomical abnormalities obtained using 3D-CT allowed the surgery to be performed safely.