22.腸管子宮内膜症

Enteric Endometriosis

要旨　腸管子宮内膜症は性成熟期の女性の直腸・S状結腸に好発する．腹痛，便通異常，便柱狭小，腹部膨満，血便などの症状がみられ，約半数で月経前から月経中に症状が増悪する．画像診断上は粘膜下腫瘍として捉えられることが多いが，腸管壁への浸潤の程度によって画像所見に様々なパターンを来す．X線では横走ひだの集中を伴う粘膜下腫瘍様の隆起や，鋸歯状の辺縁が特徴的である．粘膜面に病変が存在する場合には，大小不同の顆粒集簇ないし敷石像類似の所見，網目状構造がみられる．月経周期による所見の変化は本症に特異的である．内視鏡でも同様であるが，全体像の把握はX線が優れており，生検診断も低率である．

　Enteric endometriosis is a disorder of sexually-matured women. It occurs mainly in the rectum and sigmoid colon. Symptoms are abdominal pain, altered bowel movement, small caliber of stool, bloating, hematochezia, etc. These complaints worsen before and during menstruation in half of the cases. By imaging modalities, this disorder is generally recognized as a submucosal tumor with variable features depending on the degree of extension. Barium enema X-ray is the most reliable diagnostic tool. Submucosal tumor-like prominence with transverse ridging and serrated margin and narrowing in various degrees are characteristic X-ray findings. When the mucosal layer is involved, aggregation of variously sized granules, cobblestone-like appearance, or reticular structure is observed. That these findings vary according to the menstrual cycle is specific for this disorder. Similar findings can be observed by endoscopy, but, X-ray is superior for recognition of the total image of a lesion. Furthermore, the yield of biopsy is very limited.