十二指腸非乳頭部上皮性腫瘍と腫瘍様病変の内視鏡所見—内視鏡的鑑別診断を含めて

Clinical and Endoscopic Features of Superficial Non-ampullary Duodenal Epithelial Tumors and Tumor-like Lesions

要旨●当科で病理組織学的に確定診断した十二指腸表在性上皮性腫瘍（NETを除く）52例54病変および腫瘍様病変18例18病変を対象として，その臨床的特徴を遡及的に検討した．上皮性腫瘍は粘液形質から腸型腫瘍17例17病変（腺腫15例，腺癌2例），胃腸混合型腫瘍8例8病変（腺腫5例，腺癌3例），胃型腫瘍27例29病変（腺腫12病変，NUMP 15病変，腺癌2病変）に分類された．腸型腫瘍および胃腸混合型腫瘍は25例中21例（84.0%）に白色化を伴っていた．胃型腫瘍の肉眼型はSMT様隆起が29病変中17病変（58.6%），0-I型が10病変（34.5%）であった．胃型腺腫およびNUMPの病変表面は過半数の症例で胃腺窩上皮様領域を面状に認めた．腫瘍様病変はBrunner腺過形成・過誤腫7例，腺窩上皮型過形成性ポリープ7例，Peutz-Jeghers型ポリープ4例が診断されていた．Brunner腺過形成・過誤腫7例中4例はSMT様の形態を呈し，5例は表層に胃腺窩上皮化生を伴っていた．十二指腸の内視鏡検査において，腸型腫瘍は白色化に着目することが病変の拾い上げに有用であるが，胃型腫瘍に関しては面状の胃腺窩上皮様領域を伴う孤在性の隆起に着目することが拾い上げ診断に有用な可能性がある．胃型腫瘍と胃型形質を呈する腫瘍様病変との内視鏡的鑑別は容易ではないが，ともに隆起の様相が目立つ病変が多いため術前生検による線維化の問題が少ないこと，加えて，術前生検の正診率も比較的高いことから，両者の鑑別には生検による病理組織学的な評価を組み合わせることが有用と考えた．

　We retrospectively examined the clinical features of superficial non-ampullary duodenal epithelial tumors that were histopathologically diagnosed by endoscopic resection or surgical resection at our department. In total, 17 lesions from 17 cases of duodenal tumor of the intestinal phenotype（15 adenomas and two adenocarcinomas）, eight lesions from 8 cases of duodenal tumor of mixed gastric and intestinal phenotype, and 29 lesions from 27 cases of duodenal tumor of the gastric phenotype were diagnosed. We observed duodenal tumors of intestinal phenotype and mixed gastric and intestinal phenotype in the descending portion in 17 cases（68%）. Regarding the macroscopic appearance, 13 lesions（52%）were flat and 12（48%）were protruded. WOS（White opaque substance）was detected in 21 lesions（84.0%）in duodenal tumors of the intestinal phenotype and mixed gastric and intestinal phenotype. We observed duodenal tumors of the gastric phenotype in the duodenal bulb in 22 cases（75.9%）. Of the 25 duodenal tumors of the gastric phenotype, 17 lesions（58.6%）had submucosal tumor-like morphology and 10（34.5%）were protruded. Duodenal tumors of the gastric phenotype often exhibited gastric-like mucosa on the surface layer.

　Regarding the tumor-like lesions, 7 cases of Brunner's gland hyperplasia and hamartoma, 7 cases of crypt hyperplasia/hyperplastic polyps, and 4 cases of Peutz-Jeghers type polyps were diagnosed using endoscopic resection. Of the 7 cases of Brunner's gland hyperplasia/hamartoma, 4 exhibited submucosal tumor-like morphology and 5 exhibited gastric-like mucosa on the surface layer.

　WOS may be useful for the detection of duodenal tumors of the intestinal phenotype and islands of gastric epithelium on the surface of the protruding lesions may be helpful for the detection of duodenal tumors of gastric phenotype.

　Accurate endoscopic diagnosis of duodenal epithelial tumors and tumor-like lesions is challenging. The macroscopic appearance of duodenal tumor of the gastric phenotype is often protruded and preoperative biopsy diagnosis indicates relatively high accuracy ; therefore, preoperative biopsy might be useful for the differential diagnosis between duodenal epithelial tumors of gastric phenotype and tumor-like lesions.