非乳頭部十二指腸MP癌の1例

Non-ampullary Duodenal Cancer with Muscularis Propria Invasion, Report of a Case

要旨●70歳代，女性．EGDで十二指腸球部後面に発赤調の15mm大Type 0-Iを認めた．インジゴカルミン色素撒布像では，送気伸展下で立ち上がりがSMT様の形態を呈していた．NBI併用拡大内視鏡観察では，頂部に不整な微小血管構築像を認め，表面微細構造は不整かつ一部不明瞭化しており，WOSは陰性であった．EUSでは第4層の肥厚を認めた．総じてMP癌と診断し，腹腔鏡下幽門側胃切除＋球部切除術＋D2郭清を行った．病理診断は深達度MPの高分化管状腺癌で，リンパ節転移は認めず，免疫組織化学染色では胃型の粘液形質を呈していた．十二指腸MP癌の診断は，他の消化管癌と同様に内視鏡およびEUS所見が重要であるが，加えてSNADETと同様に粘液形質を考慮することも重要である可能性がある．

　A female patient in her 70s underwent esophagogastroduodenoscopy, revealing a 15-mm reddish type 0-I lesion on the posterior aspect of the duodenal bulb. Indigo carmine chromoendoscopy demonstrated a submucosal tumor-like elevation under insufflation. A clear demarcation line（DL）between the depressed area at the apex between the surrounding mucosa, an irregular microvascular pattern in the interior of the depression, and an irregular and partially obscure microsurface pattern with a DL were revealed on magnifying endoscopy with narrow-band imaging. The lesion was negative for the white opaque substance. Endoscopic ultrasonography（EUS）revealed thickening of the fourth layer. Based on these findings, the lesion was diagnosed as a muscularis propria（MP）invasive carcinoma, and laparoscopic distal gastrectomy and duodenal bulb resection with D2 lymph node dissection were performed. A well-differentiated tubular adenocarcinoma with MP invasion, without lymph node metastasis, was confirmed on histopathological examination. Immunohistochemical staining for the mucin phenotype demonstrated the gastric type. The diagnosis of duodenal MP cancer, similar to other gastrointestinal cancers, depends on endoscopic and EUS findings. However, considering the mucin phenotype may also be crucial as with superficial nonampullary duodenal epithelial tumors.