腹腔鏡下胆囊摘出術時に使用した非金属製非吸収性体内用結紮クリップ（non-absorbable polymer clip : NAPC）により炎症性偽腫瘍を形成した1例

A case of inflammatory pseudotumor caused by non-absorbable polymer clip （NAPC, Hem-o-Lok®） in laparoscopic cholecystectomy

◆要旨：症例は80歳男性で，腹腔鏡下胆囊摘出術の既往がある．CTで総胆管結石を指摘され，内視鏡的胆道結石除去術が施行された．経過観察画像で肝門部胆管に胆管癌を疑う腫瘤性病変を指摘され，胆管癌疑いの診断で腹腔鏡下胆管切除，胆道再建術を施行した．切除した総胆管に存在した腫瘤の内部には，非金属製非吸収性クリップ（NAPC: Hem-o-Lok^®）を認め，クリップに起因する炎症性偽腫瘍と診断した．肝胆膵領域においてNAPCにより炎症性偽腫瘍を形成した報告は，われわれが検索し得た限りない．一方，腹腔鏡下肝切除術の普及に伴い，肝胆膵領域でもNAPCの使用頻度が増えている．腹腔鏡下手術既往のある患者では，NAPC等による炎症性偽腫瘍の可能性を考慮し診療にあたることが必要であると考えられた．

　An 80-year-old man with a medical history of laparoscopic cholecystectomy underwent endoscopic sphincterotomy （EST） for choledocholithiasis which was diagnosed on abdominal CT image taken to evaluate an abdominal aortic aneurysm. Follow-up MRCP after EST indicated a mass in the upper bile duct which was suspected to be cholangiocarcinoma. Since malignancy could not be ruled out by preoperative IDUS, laparoscopic bile duct resection and reconstruction were performed. The resected mass located in the common bile duct was covered with granulation tissue, and we found a non-absorbable polymer clip （NAPC ; Hem-o-Lok^®） inside. Pathological diagnosis was an inflammatory pseudotumor （IPT） caused by a migrated NAPC. NAPCs are being used more frequently with the widespread use of laparoscopic liver resection. It is difficult to discriminate IPT from malignant tumor on preoperative imaging. Here, we recommend recognizing the possibility of IPT as a differential diagnosis in patients who have undergone laparoscopic surgery.