尿管腫瘍と鑑別困難であった後腹膜線維症

A Case of Retroperitoneal Fibrosis Mimicking a Ureteral Tumor

　症例は30歳，女性。右水腎症の精査目的で当科に入院した。CT, MRIにて骨盤内右側に径5cmの楕円形の不均一な腫瘤を認めた。順行性腎盂造影では，右尿管下部の狭窄とその一部に造影剤の貯留を呈していた。尿管腫瘍の術前診断にて手術を施行したが，術中診断は後腹膜線維症であり，腫瘤切除および尿管端々吻合術を施行した。術後1か月間ステロイドを投与し，その後中止した。術後約1年半を経過しているが，再発を認めていない。

A 30-year-old female with right hydronephrosis was admit-ted to our hospital. Computed tomography and magnetic resonance imaging showed a right lower periureteral heterogenous mass. Antegrade pyelography revealed stenosis with pooling of contrast medium at the right lower ureter. Although a ureteral tumor was suspected preop-eratively, tumor extirpation including the ureter and end-to-end anastomosis of the ureter was performed after confirming the diagnosis of retroperitoneal fibrosis by frozen section during surgery. She had no recurrence 1 year and a half postoperatively.