非乳頭部十二指腸腺腫・癌の拡大内視鏡診断—自施設での考え方

Endoscopic and Clinicopathological Features of Superficial Non-ampullary Duodenal Tumors Based on Mucin Phenotypes and Histopathological Atypia

要旨●今回，当院での非乳頭部十二指腸上皮性腫瘍（NADET）における粘液形質に基づいた臨床病理学的・内視鏡的特徴について解析を行った．当院で内視鏡的ないし外科的切除を行い，免疫組織化学的に粘液形質の評価を行ったNADET 150病変において，胃腸混合型および分類不能型形質を除いた胃型NADET 19例と腸型NADET 73例に対して，臨床的・内視鏡的特徴について比較検討を行った．胃型NADETは球部に多く発生し（94.7%），発赤調（78.9%）で，0-I様病変が多く（68.4%），白色光観察にて分葉状・顆粒状構造を示し（63.2%），NBI併用拡大観察（M-NBI）では卵円形の腺窩辺縁上皮（66.7%），dense pattern（60.0%），窩間部の開大（80.0%）が特徴的であった．一方，腸型NADETでは，下行部に多く発生し（75.3%），同色〜白色調で（71.2%），0-IIaないし0-IIc様病変が多く（84.9%），M-NBIではWOS陽性（90.0%），LBC陽性（94.3%）が特徴的であった．NADETにおける胃型形質および腸型形質に特異的な内視鏡所見が明らかとなり，それぞれの内視鏡的鑑別は可能と考えられるが，一部に非典型例が存在するため注意が必要である．今後は用語の統一を含め，診断精度の高い内視鏡診断アルゴリズムの作成が期待される．

　Mucin phenotypes of 150 lesions of NADETs（non-ampullary duodenal epithelial tumors）that were resected by endoscopic or surgical procedures at our hospital were assessed immunohistochemically. After excluding mixed and unclassified phenotypes, endoscopic and clinicopathological findings were compared between the GP（gastric phenotype, n＝19）and the IP（intestinal phenotype, n＝73）. Nearly all GP lesions（94.7%）were located in the first portion of the duodenum. The GP group was endoscopically characterized as follows：reddish color（78.9%）, types 0-I（68.4%）, lobular/granular pattern（63.2%）in white light imaging and oval-shaped marginal epithelium（66.7%）, dense pattern（60.0%）, and dilatation of the intervening part（80.0%）in M-NBI（magnifying endoscopy with narrow-band imaging）. Most IP lesions（75.3%）were located in the second position of the duodenum. The IP group was endoscopically characterized as follows：isochromatic or whitish color（71.2%）and types 0-IIa or 0-IIc（84.9%）in white light imaging, white opaque substance（90.0%）, and light-blue crest（94.3%）in M-NBI. This study clarified specific endoscopic findings for GP and IP in NADETs, however some cases were atypical. Although lesions with mixed phenotypes may show endoscopic features of both phenotypes, whether the histopathological phenotypic findings correlate with endoscopic phenotypic findings remains unclear ; thus, further investigation is needed.