消化管に限局した原発性AL型アミロイドーシスの1例―長期経過を含めて

Gastrointestinal Amyloidosis of AL Type with Reference to Serial Changes in Duodenal Lesions, Report of a Case

要旨　患者は初診時59歳，男性．大腸の潰瘍性病変を契機として，消化管生検でアミロイドーシスが疑われたため入院となった．十二指腸と上部小腸にKerckringひだの肥厚と粘膜下腫瘍様隆起の多発を認め，全身精査の結果，消化管に限局した原発性AL型アミロイドーシスと診断した．その後，70歳までの11年間無治療で消化管病変を含めた経過観察が可能であったが，大腸病変の再発はなく，臨床的に他臓器のアミロイドーシスを示唆する徴候は出現しなかった．X線・内視鏡検査では，十二指腸の粘膜下腫瘍様隆起にわずかに増大傾向を認めるのみであった．一般に原発性アミロイドーシスの予後は不良とされているが，消化管に限局したAL型の経過は良好である可能性が示唆された．

　A 59-year-old man was admitted to our hospital because of a sudden onset of hematochezia. Colonoscopy revealed multiple ulcers in the sigmoid colon. Histological examination of the biopsy specimens revealed amyloid deposits of AL type. Endoscopic and radiographic examination of the gastrointestinal tract showed thickened folds and multiple submucosal tumors in the duodenum and the jejnum, where amyloid deposits were confirmed histologically. Other organs were not affected by amyloidosis. These findings suggested a diagnosis of primary gastrointestinal amyloidosis of AL type. During a subsequent period of 11 years, there was no obvious progression in the gastrointestinal lesions. Our case suggests that primary gastrointestinal amyloidosis of AL type may have an indolent clinical course.