胃多発壁内憩室症を呈したcollagenous gastritisの1例

Collagenous Gastritis Presenting as Multiple Gastric Intramural Diverticulosis, Report of a Case

要旨●患者は40歳代，男性．症状なく，検診異常を契機に当院を紹介され受診した．胃X線造影検査では粘膜は全体に粗糙で，胃体部ではひだが消失し大小の類円形で丈の低い透亮像が多発していた．さらに，胃体部大彎には小さなカフスボタン状のニッシェが多発していた．EGDでは胃体部優位に高度の粘膜萎縮を認め，前後壁を中心に大小類円形で丈の低い粘膜が島状に多数存在し，その一部では内部に浅く緩やかな陥凹を伴っていた．胃体部大彎では，粗糙な顆粒状粘膜を背景に楔状〜小孔状の開口部を呈する深い陥凹が多発していた．胃体部前壁の類円形島状粘膜辺縁の狙撃生検では，島状粘膜部で萎縮に乏しい胃底腺粘膜の所見が，その周囲部では高度の萎縮と偽幽門腺化生に加え，上皮下を中心に粘膜固有層にcollagen bandの沈着と慢性炎症細胞浸潤が認められcollagenous gastritisと診断した．胃体部大彎の多発陥凹は，collagenous gastritisで知られる萎縮から取り残された粘膜島の中央が緩やかに陥凹する現象に引き続き，慢性の炎症機転が進行することにより生じた壁内憩室症と考えられた．

　A 46-year-old asymptomatic man was referred to our hospital for further assessment of abnormal findings obtained from a barium X-ray of the stomach conducted during a health checkup. Gastroscopic examination revealed diffuse mucosal atrophy, which is more prominent in the gastric body than in the antrum. Moreover, multiple round or granular mucosal islands were scattered in the anterior or posterior wall of the gastric body. The surface of some round mucosal islands had shallow superficial depressions. Multiple deep depressions with small round or wedge-shaped orifices were also observed in the great curvature of the gastric body. Endoscopic ultrasonography revealed that these depressions were indicative of intraluminal diverticula. Biopsy revealed foveolar atrophy with chronic mucosal inflammation and a thickened eosinophilic band-like deposition beneath the epithelium, which yielded positive results for Azan staining and negative for Congo red or amyloid staining. These findings were consistent with those of collagenous gastritis. The biopsy results of another specimen collected from the edge of the round mucosal island of the gastric body did not reveal any remarkable findings, suggesting chronic inflammation inside the round mucosal islands. In contrast, the typical findings of collagenous gastritis, as described above, were found on the outer part of the round mucosa, indicating that collagenous gastritis causes diffuse, noncomparable, map-like mucosal inflammation and atrophy. In this case, multiple intramural diverticulosis progressed to collagenous gastritis.