上行結腸から終末回腸にかけての区域性腸炎像を呈した家族性地中海熱関連腸炎（地中海熱遺伝子関連腸炎）の1例

Familial Mediterranean Fever with Segmental Entero-colitis, Report of a Case

要旨●患者は70歳代，女性．約4年前より，数か月に1回の周期で発熱と右下腹部痛が出現し，3〜4日間持続した後に自然軽快することを繰り返していた．今回も同様に発熱と右下腹部痛が出現したため，201X年に当科を受診した．大腸内視鏡検査では近位上行結腸から盲腸，終末回腸にかけて連続するびまん性，全周性，区域性の発赤調粗糙粘膜面を認め，同領域内に境界明瞭な小潰瘍の多発と回盲弁の変形・開大を認めた．同領域からの生検ではやや好中球浸潤が目立つ非特異的な慢性炎症細胞浸潤を認めた．また，注腸X線造影検査では近位上行結腸腸間膜付着側に腹膜炎を示唆する硬化所見を認めた．その後，発熱，腹痛は数日で自然消失し，内視鏡上も腸炎の軽快傾向を認めた．家族性地中海熱を疑い遺伝子検査を施行したところ，MEFV遺伝子exon2（G304R）ホモ変異を認めた．他疾患の除外診断とコルヒチンへの反応性に基づいて家族性地中海熱関連腸炎（MEFV遺伝子関連腸炎）と診断した．以後，コルヒチンの継続投与により腸病変は軽快し，発熱，腹痛の再燃なく経過している．本例では，X線造影検査で腸炎の罹患部位に一致して腹膜炎が存在することが画像的に示唆されたこと，加えて，定点生検により，内視鏡的に区域性腸炎像を認めた範囲以上に広範な腸管炎症が潜在している可能性が病理組織学的に示唆されたことなど，本腸炎の病態を考えるうえで興味ある臨床所見と病理組織学的所見を認めたので報告する．

　The patient was a 75-year-old woman who had been suffering from pyrexia and lower right quadrant pain, which had repeatedly occurred every few months and had then spontaneously improved after several days since approximately four years before her initial visit. Presently, the patient developed pyrexia and lower right quadrant pain and thus consulted our department in 201X. Results of a colonoscopy examination revealed diffuse, circumferential, and segmental redness with coarse mucosa extending continuously from the proximal ascending colon to the cecum and terminal ileum ; meanwhile, in the same area, multiple well-circumscribed small ulcers and ileocecal valve incompetence were observed. Biopsy of the coarse red mucosa revealed slight neutrophilic infiltration and non-specific chronic inflammatory cell infiltration. Furthermore, radiographic contrast revealed sclerosis features, suggesting peritonitis at the mesenteric side of the proximal ascending colon. Several days later, symptoms of pyrexia and abdominal pain spontaneously disappeared and enteritis tended to improve on colonoscopy. Upon suspicion of familial Mediterranean fever, genetic screening was performed, which revealed a homozygous mutation in exon 2（G304）on MEFV. Based on exclusion diagnosis of other diseases and responsiveness to colchicine, a diagnosis of familial Mediterranean fever-related enteritis（MEFV-related enteritis）was made. Thereafter, continuous colchicine therapy improved the intestinal lesions, and the patient progressed without flare-up of pyrexia and abdominal pain. Considering the condition of enteritis in the present case, we observed interesting clinical findings and histopathological findings, such as peritonitis consistent with the site affected by enteritis on barium enema. Furthermore, histopathological analysis of specific-site biopsy suggested possible extensive latent enteritis beyond the area observed with colonoscopy, indicating segmental enteritis.