急性胃粘膜病変との画像的鑑別に苦慮した4型胃癌の1症例

Atypical Type 4 Carcinoma of the Stomach Difficult to Differetiate from Acute Gastric Mucosal Lesion, Report of a Case

要旨　患者は，58歳，男性．上腹部痛を主訴に来院し，胃内視鏡検査にて幽門前庭部の多発する不整形のびらん/潰瘍性病変を認めた．胃内視鏡像では，典型的な急性胃粘膜病変と考えられたが，特殊胃炎（胃梅毒，Crohn病）を疑い胃生検を施行した．病理診断にて，低分化腺癌と診断された．術前精査で癌浸潤は幽門前庭部から体上部までと判断し，胃全摘術が施行された．病理組織学的所見には，幽門前庭部から体下部までは壁の肥厚（特に粘膜下層）を伴う癌細胞浸潤〔se（＋），aw（＋）〕がみられたが（深部浸潤型），体中部から噴門部にかけては線維性増殖はほとんどなく主に粘膜筋板直下での広範な癌細胞浸潤（表層拡大浸潤型）を認めた4型胃癌であった．急性胃粘膜病変との鑑別や癌浸潤範囲同定に難渋した4型胃癌症例を経験したので，病理組織学的検討も加え報告する．

　A 58-year-old man was admitted to our hospital with upper abdominal pain. Endoscopic findings revealed multiple small shallow ulcerations and erosions at the antrum. Relying on the first endoscopic examination, we diagnosed acute gastric mucosal lesion, but we suspected gastric syphilis or Crohn's disease. Biopsied specimens taken from the lesions indicated poorly differentiated adenocarcinoma. Total gastrorectomy was carried out, and histopathological examination revealed a poorly differentiated adenocarcinoma (Type 4) measuring 27.5 × 18 cm in size, with a noticeable depth of serosal exposure and a positive anal wedge. Microscopical picture of the antrum showed the carcinoma covering the whole wall associated with marked submucosal fibrosis, but, at the middle gastric body, the carcinoma between the intramuscular mucosa and the submucosal layer was not associated with fibrosis. We consider that this case is highly interesting for the differential diagnosis of advanced gastric cancer (Type 4), as opposed to acute gastric mucosal lesion which was especially difficult to establish.