内視鏡所見からみた診断手順と治療適応─非乳頭部十二指腸上皮性腫瘍

Endoscopic Diagnosis and Treatment of Superficial Non-ampullary Duodenal Epithelial Tumors

要旨●本邦において表在性非乳頭部十二指腸腫瘍の内視鏡的・外科的切除件数は急速に増加している．しかし，治療方針決定に重要な低異型度腺腫と高異型度腺腫/表在癌との内視鏡的鑑別点などは明らかになっていない．国内多施設アンケート調査によって396病変を集積・解析した結果，発赤調，腫瘍径≧6mmは高度異型腺腫/表在癌において有意に頻度が高く，術前診断において内視鏡の正診率は生検組織より高かった．腺腫/表在癌に対する標準的内視鏡治療法はEMRと考えられる．ESDは偶発症発生率（穿孔率30％前後）が高いことから，現時点において，標準的とはなりえない．SM浸潤癌の報告数は極めて限られており，今後，症例の集積が必要である．

　We defined SNADETs（superficial nonampullary duodenal epithelial tumors）to include adenomas and adenocarcinomas developed in nonampullary duodenal sites. The number of SNADETs treated using endoscopic or surgical resection is dramatically increasing in Japan. Endoscopic features of SACs（superficial adenocarcinomas）, including high grade adenomas, remain unclear because SNADETs are still uncommon. We conducted a multicenter case series study using questionnaires to conduct surveys and collect the data of 364 patients with 396 SNADETs. Compared with low-grade adenomas, a significantly greater number of SACs were found in tumors that were solitary, ≧6mm in diameter, or predominantly red in color. Preoperative endoscopic diagnosis indicated significantly higher accuracy for SAC of final histology than preoperative biopsy. At present, EMR is the standard procedure for high-grade adenomas and mucosal carcinomas smaller than 20mm because ESD has a high perforation rate of approximately 30%. As submucosal carcinomas are very rare among SNADETs, little is known about their endoscopic features, metastatic rate, and the relationships between the degree of submucosal invasion（depth or lymphovascular invasion）and lymph node metastasis. Further studies are warranted to establish the clinicopathological features of submucosal carcinomas.