直腸原発gastrointestinal stromal tumorによる尿閉

Urinary retention caused by the gastrointestinal stromal tumor of rectum

　患者は54歳，男性。排尿困難を主訴に当院を受診した。超音波検査で両側水腎，尿閉を認め，バルーンカテーテルを留置し約1,500mlの尿流出を認めた。尿閉解除後も右腹部に鵞卵大腫瘤を触知したため，精査目的に入院した。直腸診で肛門は著しく狭窄，直腸壁は石様硬であった。腫瘍マーカーはいずれも正常値であった。腹部CT，MRI検査にて直腸付近に長径約26cmの巨大な腫瘍を認めた。入院後イレウスをきたし，人工肛門造設術を施行した。確定診断のため経肛門的直腸生検を施行し，病理組織化学的に悪性gastrointestinal stromal tumor（GIST）と診断された。現在鎮痛剤による疼痛コントロールと定期的なバルーンカテーテルの交換を行っている。

　A 54-year-old man with the chief complaint of difficult urination was seen at our hospital. Balloon catheter was indwelled immediately because of bilateral hydronephrosis and urinary retention. He was admitted subsequently because a goose's egg-sized mass was palpated in right abdominal wall. Severe anal stricture with very hard anterior wall of rectum were recognized on digital rectal examination. Tumor markers such as CEA,CA19-9 and PSA were unremarkable. CT and MRI revealed a giant mass with approximately 26cm in diameter near the rectum. Colostomy was constructed owing to occurrence of ileus after admission. The giant mass was diagnosed as malignant gastrointestinal stromal tumor（GIST）immunohistochemicaly obtained by transrectal needle biopsy of rectum. Now we performe pain control using analgesics and periodic exchange of balloon catheter.