扁平ポリープ様異型上皮病巣にみられた早期胃癌の1例

REPORT ON A CASE OF EARLY GASTRIC CANCER FOUND IN SESSILE POLYPOID LESION

Ⅰ．はじめに

　異型上皮病巣はしばしば隆起性病変やⅡ型早期胃癌の疑われる病巣に出現して，早期胃癌診断の1つの重要な課題となってきた．

　胃生検が現在のところ最も確実な診断法とされるに至って，この異型上皮は一層組織診断の対象となり，その悪性度が種々論じられている．

　今回の症例は比較的短期間に病巣の著明な進展がみられたことと，広い異型上皮病巣の中に，顕微鏡的な微小瘤が含まれており，異型上皮の悪性度についての判定が問題となったもので，早期胃癌の進行度と異型上皮の悪性度判定上興味ある症例と考え報告する．

　A 43-year-old man visited Sapporo National Hospital for a thorough examination of the stomach in February, 1967. Two months before a local spasm on the greater curvature of the body had been confirmed by means of indirect radiographic gastric mass survey. By endoscopic and X-ray examination a small polypoid lesion was found in the greater curvature side of the antrum.

　In Oct., '67, he received a follow-up examination. Then it was suspected that the lesion had become malignant, because the small elevated areas, as shown by compression technique in X-ray examination, looked, through endoscopic observation, like an irregular polypoid lesion with faded colour, surrounded by hyperemic mucosa.

　On Nov. 30, '67 subtotal gastrectomy was done under tentative diagnosis of gastric cancer. The resected stomach revealed a sessile polypoid area, 4×3.5cm in size, in the greater curvature of the the antrum.

　Microscopic studies were done of all the specimens obtained from this lesion by means of the step-sectioning method. It was found that the gastric pits in the lesion consisted of more or less atypical epithelia. Proliferation of the pyloric glands and their cystic dilatation formed polypoid thickening with vertical branching of the muscularis mucosae. There were found a few tiny invasive carcinomas within these atypical epithelia. These were determined as definitely malignant on the basis of such findings as “front formation”, “budding”, “lost polarity” etc. No infiltration of carcinoma through the muscularis mucosae and no metastases to other regions of the stomach were found.

　It was concluded that the atypical epithelia of the sessile polypoid proliferation might be followed by carcinoma in situ.