肺非結核性抗酸菌症に合併した消化管アミロイドーシスの1例

Gastrointestinal Amyloidosis Secondary to Pulmonary Non Tuberculosis Mycobacteriosis, Report of a Case

要旨●患者は70歳代，女性．Mycobacterium aviumによる肺非結核性抗酸菌症で5年前から治療中も難治であった．腹痛，下痢を主訴に入院し，大腸内視鏡検査を施行した．終末回腸に輪状傾向の浅い潰瘍が多発し，同部には微細顆粒状粘膜がみられた．一方，大腸では直腸粘膜はほぼ正常であるが，上行結腸から下行結腸には顆粒状粘膜がみられた．生検組織にて，回腸では粘膜固有層深層を中心に多量に，大腸では主に粘膜上皮直下にアミロイドA蛋白質が沈着していた．部位による内視鏡像の差は組織学的なアミロイドの沈着形式と沈着量の差によるものと考えられた．なお本邦での非結核性抗酸菌症に続発するAAアミロイドーシスは，自験例を含め6例の報告しかみられなかった．6例の平均生存期間が3.6か月と短く予後不良であり，早期発見，早期治療の重要性が示唆された．

　A 70-year-old female was diagnosed with pulmonary nontuberculous acid-fast bacterium disease（pulmonary non tuberculosis mycobacteriosis ; PNTM）due to Mycobacterium avium previously five years. The disease activity of PNTM was difficult to control. She had been experiencing abdominal pain, diarrhea, and malabsorption, and was admitted to our hospital for further examination including a colonoscopy. The findings showed villous atrophy, erosion, slight ulceration scattered at the terminal ileum and fine granular appearance from the transverse colon to the sigmoid colon. Pathologically, the endoscopic findings were reflected in the difference observed in the deposit sites of AA（amyloid A）amyloidosis on the lamina propria in the small intestine and the colon.

　The prognosis of secondary AA amyloidosis due to PNTM was approximately less than 3.6 months. It may have a fatal disease, so we must diagnose for early stage of AA amyloidosis due to PNTM.