bowel castの形成過程初期をとらえたと考えられた虚血性腸炎の1例

Acute Ischemic Colitis with Early Phase Formation of a Large Bowel Cast, Report of a Case

要旨　患者は66歳，女性．2002年12月4日より下血・下腹部膨満感を主訴に来院．大腸内視鏡検査で近位側S状結腸は血腫形成を伴って閉塞し，同部に連続する乳白色索状物を認めた．注腸X線検査では，高度の求心性狭窄部に一致して翻転した約7cmの索状透亮像を認めた．より口側への造影剤流入不能で，原因疾患不明ながら腸閉塞の診断で開腹手術を施行した．手術所見では病変部の著明な壁肥厚と基部に血腫形成を伴う長軸方向に約7cmの粘膜剥離を認め，病理学的には粘膜下層の著しい浮腫とbowel cast形成初期像と考えられる壊死性腸粘膜の剥離・出血を認め，虚血性腸炎と診断した．bowel castの報告例は12例のみで，本例はcast形成の初期像として興味深く，腸管狭窄・閉塞の一因として本疾患を念頭に置く必要がある．

　A 66-year-old woman presented lower abdominal distension and hematochezia on December 4. 2002. Colonoscopy showed severe stenosis with edema and hematoma in the proximal sigmoid-colon. Irrigography revealed a stripe 7 cm in length in the stenotic lumen. Inflow of contrast medium was unable to be brought about from the anal side into the stenotic colon. The patient underwent sigmoidectomy to remove the ileus. The resected colon revealed erosion with detachment of mucosa forming two stripes, which were milky-white in color and 7 cm in length. These desquamated sections of mucosae had continuity with the non-ischemic mucosa of the anal side and floated in the stenotic lumen. Histologically, the desquamated mucosal tissues were necrotic with remnants of glandular structures and edema. The submucosal layer was edematous with mild acute inflammatory infiltration. No granulomatous lesions or vasculitis were observed. The pathological diagnosis of this condition was acute segmental ischemic colitis with formation of a large bowel casts. Only twelve cases of such a bowel cast have been reported, but this is the first case to elucidate the early phase of large bowel cast formation. Large bowel cast should be considered one of the causes of intestinal stenosis and obstruction.