下段の図１０〜図１２で下行結腸（D）に拡張はなく，図１６と図１７で上行結腸（A）が拡張しているので図１５の1から追跡する．図９〜図１２で右腎巨大嚢胞（cyst）により背側から圧迫されているので同部位では上行結腸の拡張を認めないが，壁に異常所見を認めず閉塞を起こす病変は存在しない．上行結腸は図７の9より再拡張し図２の14で閉塞する．図２〜図４の↑が閉塞の原因病変と思われ，横行結腸癌と診断する．手術および病理所見：図Aが切除標本で，横行結腸癌（白矢印：well differentiated adenocarcinoma）．

参考症例（横行結腸脾弯曲部癌）：88歳女性．4日前から排便が無く，3日前から上腹部痛が出現した．腹部が膨満し徐々に腹痛が増強したので来院．腹部は膨満を認め心窩部から左季肋部に圧痛がある．下段の図９で4の横行結腸も，下行結腸（D）もガスで拡張しているので下行結腸を肛門側へ追跡する．図１２で虚脱するが壁に異常所見を認めないので，面倒だが図１２の上行結腸１から追跡してみると図１６の20〜図１３の23で拡張を失うが図１１の25からまた拡張し始めるので追跡を続行する．図６の30で完全に虚脱し，図５〜図９の↑が造影効果を受ける壁肥厚と腫瘤を示し閉塞病変である．図３の33〜図１０のDまでガスで拡張しているので不完全閉塞である．図１１〜図１５の△は壁内気腫であり，早期の減圧法を考慮すべきである．翌日閉塞部の口側に人工肛門を造設したが，横行結腸（脾弯曲部）癌が確認され，後日左半結腸切除を施行した．病理：adenocarcinoma．

文献考察：右側閉塞性大腸癌の予後は悪い．
Am J Surg. 2004 Apr;187(4):497-500.
Long-term prognosis of patients with obstructing carcinoma of the right colon.
Wang HS, Lin JK, Mou CY, Lin TC, Chen WS, Jiang JK, Yang SH.

BACKGROUND: The long-term prognosis of patients with colon cancer is dependent on many factors. The aim of this retrospective study was to assess the long-term prognosis of patients with obstructing carcinoma of the right colon. METHODS: From 1981 to 1988, 256 patients at the Veterans General Hospital-Taipei who were status postcurative resection of right colon adenocarcinoma were classified as obstruction group (n = 35) or nonobstruction group (n = 221) as appropriate. RESULTS: Analysis revealed no differences in age, sex, tumor location, or stage (P >0.05) between the two groups. However, the overall and distant recurrence rates were significant higher in obstructed patients than in nonobstructed patients. Further, long-term crude and cancer-specific survival rates were significantly lower in obstructed patients when examining either overall patient outcome or stage-matched outcomes. Multivariate analysis demonstrated that obstruction and tumor stage were both independent prognostic factors. CONCLUSIONS: Obstruction status was an independent prognostic factor for patients with right colon carcinoma. The long-term prognosis of patients with obstructing carcinoma of the right colon was poor.PMID: 15041498