十二指腸上皮性腫瘍の臨床診断と治療―腺腫・癌

Magnifying Endoscopy with Narrow Band Imaging for Diagnosis of Nonampullary Duodenal Adenomas and Early Cancers

要旨　十二指腸の腺腫と早期癌19例の臨床的特徴と内視鏡所見を検討した．ルーチン内視鏡検査での頻度は腺腫0.039％，早期癌0.017％と極めて低かった．腺腫の80％は下行部に存在していた．通常内視鏡観察では腺腫と癌の鑑別は困難であったが，絨毛の白色化は病変の発見に有用な所見と思われた．NBI併用拡大内視鏡観察ではすべての腫瘍は不均一な粘膜模様を呈した．表面微細構造は管状，敷石状，乳頭状と絨毛様構造に分類された．腺腫では管状構造，敷石状構造が主体であったが，癌は絨毛様構造を呈す傾向にあった．微小血管構築像に関してはnetwork patternを腺腫の2例に認めたが，癌では認めなかった．癌では微小血管に口径不同・拡張といった不整像が観察される傾向があり，NBI併用拡大内視鏡観察は腺腫と癌の鑑別診断に有望な手段である．現時点では内視鏡所見のみでは厳密に両者を鑑別することは困難で，早期発見し完全生検を目的に内視鏡治療を行うべきであろう．今後は絨毛の白色化の状態や微小血管構築像を中心に，多くの知見を集積することが急務である．

　19 cases of nonampullary duodenal adenomas and early cancers were examined, using conventional endoscopy and magnifying endoscopy with narrow band imaging（NBI）. Their frequency under routine endoscopy was extremely low with adenoma at 0.034％ and early cancer at 0.017％. 80％ of adenomas were located in the 2nd part of the duodenum. Of the 19 lesions, 16（84％）had a whitish villous color could be a helpful sign for the recognition of nonampullary duodenal intraepithelial tumors, under conventional endoscopy. Observation with magnified NBI might be a promising approach for the differential diagnosis of adenoma and cancer. The differential diagnosis of adenoma and cancer has been regarded as important. However, it was difficult using conventional endoscopy. On narrow-band imaging magnified endoscopy, all tumors had a heterogeneous pattern. The mucosal microsurface structure is classified into tubular structure, cobblestone-like structure, papillary structure, and villous-like structure. Tubular and cobblestone-like structure were most frequently observed in adenomas, but carcinomas tended to present villous-like structure. Network pattern on the mucosal microvascular architecture was observed in two cases of adenoma, but was not recognized for carcinoma. Regarding nonampullary tumors, villous-like structural mucosa and abnormal vessels were able to be seen more often in cancers. Though duodenal adenoma is comparatively rare, it is difficult to distinguish it from a cancer, therefore endoscopic resection is necessary when it is located in the mucosa. Observation with magnified NBI might be a promising approach to the differential diagnosis of adenoma and cancer.