十二指腸乳頭部癌の診断―EUSの立場から

Endosonographic Diagnosis of Carcinoma of the Papilla of Vater

要旨　超音波内視鏡（EUS），ならびに超音波プローブ（IDUS）による乳頭部癌診断の意義は，腫瘍の進展度診断である．38例の乳頭部癌のうち，超音波（US）で膵胆管拡張を指摘された25例の中で5例がEUSで診断された．また，USで異常を認めなかった5例のうち1例がEUSで診断されたが，いずれもEUSの内視鏡機能による診断であった．EUSによる乳頭部病変の鑑別診断も期待されるが，EUS，IDUSとも他の画像診断法で指摘された病変の進展度を判定する手段と考えられた．EUSによる乳頭部癌の進展度正診率は十二指腸浸潤診断で84.4％，膵浸潤診断で81.3％，腫瘍進展度診断で78.1％，リンパ節転移診断で75％であった．IDUSでは，それぞれ80％，80％，70％，70％であった．満足できる成績とは言えないが乳頭部癌に対する治療法の選択を決定する際，特に縮小手術や内視鏡治療を論じる際に不可欠な検査法として評価される．

　Endosonography such as ultrasound endoscopes (EUS) and ultrasound probes (IDUS) in the diagnosis and staging of carcinoma of the papilla of Vater were discussed. Concerning the detection of a tumor mass of the papilla of Vater, five cases of 25 cases which were diagnosed as having dilatation of the bilio-pancreatic duct by ultrasonography (US) were detected by EUS endoscopically. The significance of endosonography is that it demonstrates tumor expansion which means the staging of the tumor. Discussing the staging of carcinoma of the papilla of Vater is important for decision making about therapeutic procedure such as laparotomy or endoscopic treatment. The result of the cancer staging by EUS was 84.4% in the duodenal invasion, 81.3% in the pancreas invasion, 78.1% in T staging and 75% in lymph node metastasis. On the other hand, the results by IDUS, which was carried out by intrabilio-pancreatic ductal ultrasound scanning using ultrasound probes, was 80% in the duodenal and pancreas invasion, 70% in T staging and lymph node metastasis. Endosonography in the diagnosis of carcinoma of the papilla of Vater is highly evaluated as a tool for deciding the staging of a tumor.