経過観察しえた表層拡大型早期胃癌の1例

Elevated Superficial Spreading Type of Early Gastric Cancer Observed for Two Years, Report of a Case

要旨　患者は77歳，男性．検診の胃X線および内視鏡検査で胃体部に広範な丈の低い隆起性病変を指摘された．色調は全体に褪色調で，15か所から施行した生検結果はGroup Ⅲであった．癌の合併を考慮し，手術を勧めたが拒否されたため，経過観察となった．病変は徐々に増大し，1年10か月後に生検でGroup Ⅴの結果が得られ，2年後に胃全摘術が施行された．切除胃肉眼所見では，噴門部から胃角部にかけて全周性に16.5×13cm大の丈の低い隆起を認めた．病変は局所的には胃腺腫に類似した形態を呈し，胃体中部後壁に小陥凹を認めた．組織学的には，高分化型管状腺癌が主体で，一部に中分化型管状腺癌を認めた．また，小陥凹部で粘膜下層に浸潤を認めたが，大部分は粘膜内にとどまっていた．

　Screening x-ray study and subsequent endoscopic examination of the upper gastrointestinal tract were performed on a 77-year-old man with no symptoms. These examinations revealed a wide flat elevation over the entire gastric body. The lesion was pale as a whole and 15 biopsy specimens were classified into Group Ⅲ. Although we recommended surgery, allowing for the development of carcinoma, the patient rejected it. The lesion gradually enlarged during follow-up observation. Biopsy specimens were classified into Group Ⅴ one year and ten months later and total gastrectomy with lymph node dissection was performed two years later.

　Gross observation of the resected specimen showed a flat elevated lesion, spreading from the cardiac region to the gastric angle. The whole lesion measured 16.5 cm by 13 cm. Observing the lesion partially, it was similar in form to gastric adenoma. In addition, a small irregular depression was recognized on the posterior wall of the middle of the gastric body.

　Histologically, the lesion was mainly composed of well diferentiated tubular adenocarcinoma, and moderately differentiated tubular adenocarcinoma was detected in a very small area. The carcinoma was found to be limited to the mucosa in most of the lesion, however, it had invaded the submucosa in the small depression.

　This lesion, keeping the gross appearance of gastric adenoma, spread widely and is thought to be a very rare case.