馬蹄腎を伴う直腸S状部癌に対して腹腔鏡下高位前方切除術を施行した1例

Laparoscopic high anterior resection for rectosigmoid colon cancer with a horseshoe kidney : A case report

◆要旨：症例は50歳，女性．検診で便潜血陽性を指摘された．下部消化管内視鏡検査で直腸S状部に15mm大の0-Ⅰs＋Ⅱc病変を認め，生検の結果は高分化型管状腺癌であった．腹部造影CT検査で馬蹄腎を認めた．下腸間膜動脈分岐部より尾側の大動脈と，左総腸骨動脈からそれぞれ1本ずつ腎癒合部へ流入する過剰腎動脈を認めた．尿管・性腺血管の走行異常は認めなかった．cT2N0M0 cStageⅠの術前診断で腹腔鏡下高位前方切除術D3郭清を行った．腎癒合部の隆起により下腸間膜動脈根部周囲で鉗子操作に制限を認めたが，上下腹神経叢・腰内臓神経は癒合腎腹側を走行しており，後腹膜下筋膜を背側に温存する通常の内側アプローチ剝離層で手術を安全に施行できた．

　A 50-year-old female was positive for fecal occult blood on medical examination. Colonoscopy revealed a 15 mm type 0-Ⅰs＋Ⅱc tumor in the rectosigmoid colon, and biopsy results was a well differentiated tubular adenocarcinoma. Abdominal contrast-enhanced CT scan showed a horseshoe kidney with two aberrant arteries. One artery supplied the renal isthmus from the right common iliac artery and the other directly from the aorta. There were no anomalies in the ureters or gonadal vessels. With the preoperative diagnosis of cT2N0M0 cStage I, we performed laparoscopic high anterior resection with D3 lymphadenectomy. Due to the elevation of the renal isthmus, there were restrictions around the root of the inferior mesenteric artery. However, we could safely preserve the retroperitoneal fascia using the standard medial approach because of the superior hypogastric plexus and the lumbar splanchnic nerves found on the ventral side of the horseshoe kidney.