下段の図１３〜図１６で上行結腸（A）は拡張し，下行結腸（D）は対照的に虚脱しているのでその間に閉塞がないか検索する．図１２の上行結腸１から肛門側へ追跡すると図１０の横行結腸32で閉塞する．追跡しながら壁の変化に気をつけるのだが，図１３の↑あたりから壁が肥厚し始め，図１１で完全閉塞を起こす病変（↑）となる．よく造影される短い病変だから横行結腸癌による大腸閉塞であろうと診断する．図１０〜図１４の▲は壁内気腫である．内容物が固形便の時，便周囲のガスが壁内気腫様に描出されることはあるが，内容物が液状で，壁に沿った線状のガスは壁内気腫と解釈する．壁内気腫は腸管壁の壊死または高度の虚血状態を意味することが多いので，拡張した腸管の減圧法を早期に考慮すべきである．図Aは注腸造影，白矢印が完全閉塞を起こした癌部．口側に人工肛門を造設し，後日横行結腸切除を施行した．病理：moderately differentiated adenocarcinoma．

参考症例（肝弯曲部結腸癌）：85歳男性．前日に上腹部痛が出現し，当日嘔吐が加わり来院した．腹部は膨満し下腹部に圧痛がある．図１０と図１１で上行結腸（A）が拡張し，下行結腸（D）には拡張を認めないので図９の上行結腸１から肛門側へ追跡すると，図１の９で閉塞する．図１の↑が造影効果を受ける原因病変で，癌であろうと推測する．内視鏡検査で同所見が確認され，経肛門的減圧に成功した（図A：▲）．このように右側結腸でも経肛門的減圧が可能であり，効果的である．

文献考察：閉塞（83例），穿孔（24例）または大量出血（1例）で緊急手術を要した大腸癌は全大腸癌の11.4％．
Am J Surg. 2005 Sep;190(3):376-82.
Presentation, treatment, and multivariate analysis of risk factors for obstructive and perforative colorectal carcinoma.
Alvarez JA, Baldonedo RF, Bear IG, Truan N, Pire G, Alvarez P.

BACKGROUND: It is known that emergency surgery for colorectal cancer is associated with high morbidity and mortality. The aim of this study was to assess the presentation, treatment, and outcome of patients with complicated colorectal cancer. Risk factors for morbidity and mortality were also evaluated. METHODS: From 1991 to 2002, the medical records of 107 consecutive patients undergoing emergency surgery for obstructing or perforating colorectal carcinoma were retrospectively reviewed. Information regarding patient and tumor characteristics, treatment, and outcome was recorded. Risk factors were assessed by multivariate analysis. RESULTS: Eighty-three patients (78%) had complete obstruction and 24 (22%) had perforation. Overall and major complications occurred in 70% and 34%, respectively. The mortality rate was 15%. Independent risk factors for major morbidity were perioperative blood transfusion and high American Society of Anesthesiologists (ASA) class, whereas those for mortality were older age and high Acute Physiology and Chronic Health Evaluation II (APACHE II) score. CONCLUSIONS: Emergency surgery for complicated colorectal carcinoma carries high rates of morbidity and mortality. To achieve improvements in outcome, intensive treatment after surgery in patients with risk factors is recommended.PMID: 16105522