気胸手術中に偶然発見された肺葉外肺分画症に対して二期的手術を施行した1例

Two-stage thoracoscopic resection of extralobar pulmonary sequestration incidentally found during thoracoscopic surgery for spontaneous pneumothorax : A case report

◆要旨：症例は17歳，男性．左再発性気胸に対して当科で胸腔鏡下左肺上葉部分切除術を施行した際に，偶然肺底部背側の横隔膜角部に肺との連続性がない肝臓様構造物を認めた．外観と局在から肺葉外肺分画症が疑われたが，術前に異常血管の評価が行えていないため，万が一の損傷を回避するために一期的切除は行わず手術を終了した．術後に行った造影CTで，胸部下行大動脈からの異常動脈と半奇静脈への還流静脈を伴う軟部腫瘤を左横隔膜上に認め，肺葉外肺分画症と診断した．気胸手術から3か月後に胸腔鏡下左分画肺切除術を施行した．術前に異常血管の血管径や分岐部位，走行について把握できていたため，安全な血管処理が可能であった．

　In a 17-year-old male patient, a liver-like mass without continuity with the lung was noted in the dorsal diaphragmatic angle during thoracoscopic surgery for a left spontaneous pneumothorax. Extralobar pulmonary sequestration was suspected ; however, the lesion was not resected during surgery in order to avoid aberrant vessel injury because preoperative plain computed tomography（CT） was unable to reveal the details of the aberrant vessel. Postoperative contrast-enhanced CT showed a soft-tissue mass with heterogeneous enhancement on the left diaphragm with an aberrant artery from the descending aorta and a drainage vein returning to the hemiazygos vein. Based on these findings, we diagnosed the patient with extralobar pulmonary sequestration. The lesion was resected thoracoscopically 3 months after the surgery for pneumothorax. Due to the thorough preoperative assessment, safe thoracoscopic surgery was possible and the aberrant vessel was cut safely.