消化管出血を契機に発見された異所性膵から発生したMeckel憩室癌の1例

Meckel's Diverticular Adenocarcinoma in the Ectopic Pancreas Detected During the Gastrointestinal Bleeding Survey, Report of a Case

要旨●患者は80歳代，男性．血便を主訴に前医を受診した．上部・下部消化管内視鏡検査が施行されたが出血源を認めず，小腸出血疑いで当院に紹介となった．小腸カプセル内視鏡検査では下部小腸に出血を認め，経肛門的ダブルバルーン内視鏡検査を施行した．回盲弁から100cm付近口側の回腸に15mm大の頂部に出血びらんを伴うクッションサイン陰性の粘膜下腫瘍（SMT）様隆起を認めた．病変の基部に同心円状ひだがあり，Meckel憩室の内翻を疑った．出血源と考え，腹腔鏡補助下小腸切除術を施行した．切除標本病理組織学的所見ではMeckel憩室の固有筋層から漿膜下を主座とする腺癌であった．腫瘍周囲に異所性膵を認め，腫瘍との連続性や免疫染色所見から異所性膵を発生母地とするMeckel憩室癌と診断した．

　A male patient in his 80s with a chief complaint of bloody stool visited a hospital. However, the cause of bleeding was not detected in the upper and lower gastrointestinal endoscopy. Subsequently, he was referred to our hospital with suspicion of small bowel bleeding. The capsule endoscopy revealed lower small intestinal bleeding ; thus, transanal double-balloon endoscopy was performed. At approximately 100cm oral side from the ileocecal valve, a cushion-sign negative submucosal tumor-like lesion（size, 15mm）was detected with erosion and blood oozing at the top. A concentric fold was observed at the base of the lesion, and the inversion of the Meckel's diverticulum was suspected and considered as the cause of bleeding ; thus, laparoscopic resection was performed. Histopathological findings of the resected specimen revealed an adenocarcinoma in the muscularis propria and subserosa of the Meckel's diverticulum. Ectopic pancreatic tissue was contiguous to the tumor, and immunostaining findings led to a diagnosis of Meckel's diverticular adenocarcinoma arising in ectopic pancreatic tissues.