十二指腸非乳頭部癌の病理組織学的特徴と悪性度評価

Histopathological Features Associated with Aggressive Behavior in Extra-ampullary

要旨●十二指腸非乳頭部癌36例の臨床病理学的評価を行い，特に粘液形質の意義や早期癌の悪性度因子について検討した．胃型形質癌は十二指腸近位側に発生し，腸型形質癌と比較して早期癌の割合が高いことが特徴であった．早期癌17例中，リンパ節転移陽性例は胃型形質SM癌の1例のみであった．また脈管侵襲や未分化型組織像を示した早期癌4例はいずれも胃型形質SM癌であった．限られた症例数での検討であるが，胃型形質が高悪性度に関連することが示唆された．また，腸型・腸型優位混合型進行癌の30%にMLH1欠損が認められ，免疫チェックポイント阻害薬の治療適応となりやすいと考えられる．

　We conducted a retrospective analysis of 36 extra-ampullary duodenal adenocarcinomas with a special focus on mucin phenotype as well as risk factors of nodal metastasis in early cancer. Tumors with gastric phenotype were located in the proximal duodenum and were more frequently detected as early cancer than those with intestinal phenotype. Gastric phenotype had a higher likelihood of being associated with aggressive phenotype in early cancer because all tumors with lymphovascular invasion（n＝4）, undifferentiated histology（n＝1）, or positive lymph nodes（n＝1）exhibited gastric phenotype. The results also showed a relatively high incidence of mismatch repair deficiency, particularly in tumors with intestinal phenotype. This suggests the need for an MSI test to provide patients with optimal treatment options including a checkpoint inhibitor.