IgG4関連後腹膜線維症の合併により腹腔鏡下切除と吻合に難渋したS状結腸癌の1例

A case of sigmoid colon cancer that was difficult to treat by laparoscopic resection and anastomosis due to the complications of IgG4-related retroperitoneal fibrosis for which definite diagnosis was made by laparoscopic biopsy

◆要旨：患者は64歳，女性．下部消化管内視鏡検査でS状結腸癌を認めた．造影CTで腹部大動脈周囲の後腹膜が著明に肥厚し，左水腎症も認めた．血清IgG4が高値で，IgG4関連後腹膜線維症を合併したS状結腸癌と術前診断した．尿管ステントを留置し，腹腔鏡下後腹膜生検とS状結腸切除術を施行した．後腹膜組織の迅速病理検査では悪性所見を認めなかった．S状結腸切除では，腸間膜の剝離授動や血管処理に難渋した．さらに経肛門的な腸管吻合が困難で，小開腹下に手縫い端々吻合で再建した．後腹膜生検を安全に行うには，生検部位の術前評価や生検方法が重要である．また，後腹膜線維症を合併したS状結腸切除術では，腸間膜の剝離授動や吻合に際して注意を要する．

The patient was a 64-year-old woman in whom sigmoid colon cancer was found using lower gastrointestinal endoscopy. Contrast-enhanced CT revealed marked retroperitoneum thickening near the ventral aorta and hydronephrosis of the left kidney. Her serum IgG4 concentration was elevated. The preoperative diagnosis was sigmoid colon cancer with concurrent IgG4-related retroperitoneal fibrosis. A ureteral stent was placed, followed by laparoscopic retroperitoneal biopsy and sigmoid colectomy. Rapid pathological examination of the retroperitoneal tissue revealed no malignant findings. Difficulties were encountered during dissection and mobilization of the mesentery and blood vessel treatment in sigmoid colectomy. Transanal intestinal anastomosis was also difficult; therefore, a small laparotomy was performed. Preoperative evaluation of the biopsy site and the biopsy technique are crucial to safely perform retroperitoneal biopsy. Furthermore, when performing sigmoid colectomy on cases with the complication of retroperitoneal fibrosis, due care should be taken during dissection and mobilization of the mesentery and anastomosis.