遡及的に典型的linitis plastica型胃癌までの経過を観察しえた前，潜在的linitis plastica型胃癌の2例

Retrospective Examination of the Course of Development of Pre-and Latent Linitis Plastica Type Gastric Cancer into Classical Linitis Plastica Type Gastric Cancer. Report of Two Cases

要旨　X線・内視鏡検査にて遡及的に経過観察しえたlinitis plastica型胃癌（以下，LP型癌）の2例を報告する．〔症例1〕初回X線，内視鏡検査では胃体上部前壁に粘膜ひだの集中を伴う長径20mmの不整な陥凹性病変を認めた．陥凹の周囲はやや隆起しており，粘膜ひだの腫大を認め，0Ⅱc型のSM癌と推定した．その後のX線経過で，胃体上部から胃体下部にかけて胃壁の硬化所見と粘膜ひだの肥厚，蛇行が出現し，3年9か月後にはleather bottle状の典型的なLP型癌に進展していた．〔症例2〕初回X線検査で胃体中部から胃体下部大彎に約50mmにわたる胃壁の硬化像と粘膜ひだの肥厚を認め，SM以深癌の存在が推定された．1年6か月後のX線検査では胃体下部から胃穹窿部にかけて広範な胃壁の伸展不良を認め，LP型癌へ進展していた．各X線像より，〔症例1〕初回検査時は前LP型癌，2年2か月後は潜在的LP型癌，3年9か月後は典型的LP型癌，〔症例2〕初回検査時は潜在的LP型癌，1年6か月後は典型的LP型癌と病期分類した．2症例の経過観察期間より，潜在的LP型癌より典型的LP型癌への進展速度は1.5年程度であり，少なくとも前LP型癌の時期より4年以内に典型的LP型癌に進展したことが推定される．

　We report 2 cases of linitis plastica type gastric cancer (LP-type cancer) whose course we were able to observe retrospectively by means of x-ray and endoscopic examinations. Case 1:The initial X-ray and endoscopic examination revealed an irregular depressed lesion with a long diameter of 20 mm with convergence of mucosal folds in the anterior wall of the upper portion of the gastric body. The periphery of the depression was relatively elevated, and enlarged mucosal folds were observed. Based on these findings a diagnosis of 0Ⅱc type SM cancer was made. In the course of subsequent x-ray examinations induration of the gastric wall and thickening and tortuosity of the mucosal folds from the upper to the lower portion of the gastric body appeared, and after 3 years 9 months it had progressed to classical leather-bottle type LP-type cancer. Case 2:The initial x-ray examination revealed induration of the gastric wall and enlargement of the gastric folds along approximately 50 mm of the greater curvature from the middle portion to lower portion of the gastric body, and SM or more deeply invasive cancer was diagnosed. An x-ray examination 18 months later showed poor distensibility of the gastric wall over a wide area from the lower portion of the gastric body to the convexity of the stomach, and it had progressed to LP-type cancer. Based on the radiographic findings, Case 1 was pre-LP-type cancer at the time of the initial examination, latent LP-type cancer 26 months later, and classical LP-type cancer 45 months later, whereas in Case 2 the initial examination showed latent LP-type cancer, and 18 months later it was staged as classical LP-type cancer. Based on the periods of observation of the course of these 2 cases, progression from latent LP-type cancer to classical LP-type cancer took about 1.5 years, and progression from pre-LP-type cancer to classical LP-type cancer was estimated to have taken less than 4 years.