胃囊胞の2例と本邦報告例に関する文献的考察

Report on Two Cases of Gastric Cyst and Review of the Japanese Literature

　胃囊胞は稀な疾患であり，しかも本症として文献上に報告されている症例には病理組織学的にさまざまな症例が含まれている，著者らはこれまでに2例の手術症例を経験したので，これらの症例について報告するとともに，自験例を含めて調査しえた58例の本邦報告例を対象として文献的考察を加えてみたい．

症例

　〔症例1〕39歳男子（病歴番号　730093）

　既往歴：特記すべきことなし

　家族歴：父方親族に多発性骨髄腫2例，S. L. E. 1例．

　現病歴：生来健康であったが，昭和48年1月，胃集検

をうけた際に胃角部小彎に陰影欠損像を指摘された．東大第1内科において精査を行ない，胃囊胞の診断のもとに同第1外科に入院した．

　Two cases of gastric cyst are presented with some references to the literature.

　Case-Ⅰ. A 39-year-old man was admitted to our clinic because of gastric tumor which had been found by gastric mass survey. Preoperative X-ray and endoscopic examination revealed a submucosal cystic tumor at the gastric angle. Partial gastrectomy was performed. Postoperative course was uneventful. The cyst was 3.0×2.0×1.0 cm in size, located beneath the normal mucosa at the lesser curvature of the resected specimen. The cyst contained about 6 ml of serous fluid. By laboratory examination the nature of this fluid was very like that of serum, and amylase level was also normal. Pathological diagnosis was cystic lymphangioma in the submucosal layer of the stomach.

　Case-Ⅱ. A 60-year-old man visited our clinic with a complaint of epigastric pain. X-ray and endoscopic examination showed a gastric mass with a suspicion of malignancy. The tumor was a submucosal cystic mass, which was 2.0×1.5×1.5 cm in size at the posterior wall of the gastric antrum with a small ulcer scar just proximal to this tumor. Pathological diagnosis of this mass was multiple retention cysts derived from ectopic pyloric glands in the submucosal layer of the stomach.

　We have collected 58 reported cases of gastric cysts in Japanese literature. Among various types of cystic lesions, both lymphatic type and ectopic pyloric gland type were common. The former was found in 21 cases, the latter in 16 cases, respectively. The third was aberrant pancreatic type, encountered in 7 cases.

　The others were 5 cases of simple cyst of unknown origin and 9 cases of miscellaneous lesions. The lymphatic type was rarely reported in foreign literature, but the relatively high frequency of this type seemed characteristic findings in our country. The majority of these lesions were located in the antrum or gastric angle. Lymphatic type was usually solitary and larger, compared with ectopic pyloric gland type having the tendency to be multiple and smaller. Lymphatic type was associated with gastric cancer in 5 cases, ectopic pyloric gland type in two cases, and aberrant pancreatic type in two, respectively. The relatively high frequency of the association of this lesion with cancer could be speculated as follows; some cysts might develop from retention of normal glands which escaped from cancerous infiltration or from regenerative process in ulcerated lesion, and other cysts might be found accidentally in cases of gastric cancer. No malignant change of cystic wall could be found except in one case, in which cystic degeneration was observed in the Large gastric sarcoma. Malignant gastric cyst was very low in frequency, but the possibility of it should be borne in mind.