1年間の経過で急速に増大傾向を示した粘膜下腫瘍様残胃癌の1例

Remnant Gastric Cancer Mimicking a Submucosal Tumor, that Rapidly Increased in Size Over the Period of One Year, Report of a Case

要旨●患者は70歳代，女性．十二指腸潰瘍で手術歴があり，定期検査のため近医にて上部消化管内視鏡検査を施行したところ，残胃噴門に径6cm大の粘膜下腫瘍（submucosal tumor ; SMT）様隆起を指摘された．精査加療目的で当科へ紹介され，受診となった．表面に白苔を伴い山田III型様の立ち上がりを有する隆起であり，比較的軟らかく，超音波内視鏡検査では第4層まで達する低エコー腫瘤として描出された．病理組織学的には，SMT様隆起の表層は壊死と正常粘膜に覆われ，腫瘍の露出はわずかであり，上皮性の悪性所見に乏しかった．腫瘍細胞は小型の円形〜卵円形核を有する異型の強い細胞で，充実性に増殖し漿膜外まで浸潤を認め，1型の低分化腺癌と診断された．本病変は1年間で9cm大まで増大するという急激な経過を辿り，SMT類似の形態を示し，間質反応に乏しく比較的軟らかい腫瘍のために，胃癌と診断することが困難であった．

　The patient was a female in her 70s. She had undergone partial gastrectomy for duodenal ulcer. A periodic esophagogastroduodenoscopy revealed a protruded lesion mimicking a submucosal tumor（SMT）6cm in size below the cardiac region of the remnant stomach. It was relatively soft and looked like a Yamada type-III tumor with whitish exudate. Endoscopic ultrasonography showed a homogeneous hypoechoic lesion until the 4th layer. Histologically, the surface of the ridge was covered with normal gastric mucosa and necrotic tissue. Exposure of the tumor was small. Consequently, epithelial tumor findings indicating malignancy were poor. The tumor cells were circular, small, and solid with proliferation and had invaded the serosal tissue. The tumor was diagnosed as a type 1 poorly differentiated adenocarcinoma. The correct diagnosis was difficult to conclude because the relatively soft tumor with poor stromal reaction had a form similar to the SMT and had grown rapidly at a rate of 6cm per year.