多発陥凹性病変を呈した胃限局型ALアミロイドーシスの1例

Localized Gastric Amyloidosis of AL Type Manifesting as Multiple Mucosal Depression, Report of a Case

要旨●患者は50歳代，女性．関節リウマチに対し，近医で加療されていた．腹部膨満感の精査目的で実施した上部消化管内視鏡検査で，胃体部から幽門前庭部にかけて発赤を混じた褪色調陥凹性病変の多発を認めた．背景粘膜の萎縮性変化は明らかではなく，Helicobacter pylori血清IgG抗体は陰性であった．病変部から採取した生検組織において，粘膜下層を中心とした好酸性物質の沈着を認め，免疫組織化学染色にてALアミロイドーシスと診断した．全身検索を行ったが，他臓器へのアミロイド沈着を認めず，多発性骨髄腫を示唆する所見もなかった．以上より，胃に限局したALアミロイドーシスと考えられた．

　A 50-year-old woman with rheumatoid arthritis was referred to our hospital for evaluation of multiple depressed lesions in the stomach. EGD demonstrated three depressed lesions in the stomach; one lesion in the antrum, which was depicted as a large discolored mucosal depression with scattered erosion, and the other two in the body, which were reddish mucosal depressions surrounded by the granular mucosa. EGD, mucosal atrophy was not observed in the background gastric mucosa, and the serum anti-Helicobacter pylori IgG antibody level was also negative. Despite her underlying disease, histologic examination of the biopsy specimens from these lesions demonstrated submucosal deposition of eosinophilic substances, which were immunohistochemically determined to be amyloid deposits of AL type. On systemic examination, no amyloid deposit was confirmed in her other organs, and no sign of multiple myeloma was found. Thus, the diagnosis of localized gastric amyloidosis of AL type was finally made.