粘膜下腫瘍様の形態を呈した乳頭腺癌の1例

Papillary Adenocarcinoma Presenting with Submucosal Tumor-like Morphology, Report of a Case

要旨●患者は60歳代，女性．特に症状はなく，対策型胃X線検診を受け，胃体下部大彎に頂部にニッシェを伴う大きさ2cm弱の粘膜下腫瘍様隆起を認めた．撮影技師が再現性の有無および質的診断を目的に追加撮影を行った．読影医師はニッシェの肛門側辺縁に淡い陰影斑を認めたことから，上皮性腫瘍の可能性が考えられ，読影基準カテゴリー4（癌疑い）と診断し要精検となった．通常内視鏡検査では頂部に潰瘍を伴う粘膜下腫瘍で，インジゴカルミン色素撒布像では周囲の粘膜不整が明瞭となり，NBI拡大内視鏡検査では，潰瘍周囲に不整腺管を認めた．幽門輪温存幽門側胃切除術を施行．病理組織診断では，乳頭腺癌が下方へ圧排性に浸潤発育し，粘膜下腫瘍様隆起を呈していた．また，潰瘍の肛門側辺縁に高分化腺癌の存在を認めた．病理組織診断はpType 0-I＋III＋IIc，T1b2（SM2，4,750μm），16×11×4mm，pap>tub1>tub2，gastric foveolar type，ly1，v0，pN1（1/34）であった．

　A 6X-year-old female patient visited for a regular check-up. On undergoing an abdominal X-ray as part of the population-based screening, a submucosal tumor-like projection of just less than 2cm in size accompanied by a niche in the peak of the greater curvature of the lower body of the stomach was detected. Therefore, the patient underwent further examination and investigations at our department. As rugae were absent on the body of the stomach, she was diagnosed with severe atrophy. Because detailed abdominal X-ray imaging revealed punctiform to linear barium spots around the niche with asymmetrical submucosal tumor-like protrusion area, an endothelial malignant tumor infiltrating and growing in the submucosa was diagnosed. Upper gastrointestinal endoscopy revealed a submucosal tumor accompanied by ulceration at the tip, and indigo carmine dye revealed irregular surrounding mucosa. Narrow-band imaging endoscopy revealed a large irregular duct around the ulceration. Pylorus-preserving distal gastrectomy was performed. Histopathology indicated that a papillary adenocarcinoma had infiltrated and grown downward while displacing tissue, thereby exhibiting a submucosal tumor-like appearance. The histopathological diagnosis was pType 0-I＋III＋IIc, T1b2［SM2（4,750μm）］, 16×11×4mm, pap>tub1>tub2, gastric foveolar type, ly1, v0, pN1（1/34）.