検診を契機に発見された過剰腎

A supernumerary kidney discovered incidentally on occasion of annual health checkups

　症例は51歳の女性，検診で尿潜血陽性と判定され，精査目的に当科を受診をした。DIPにて，左側に2つの腎盂，尿管を認め，さらにCT，MRIにて左側に連続性のない完全に分離した2つの腎を認めた。また，膀胱鏡でインディゴカルミン静注により尿管口は両側正常位置の他，膀胱内の内尿道口付近にも確認した。画像所見などより固有の腎被膜と腎盂，尿管を持つ腎が3つあり，どの腎も著明な水腎や萎縮を伴わない過剰腎の典型例と思われた。

Supernumerary kidney is one of the rarest anomalies of urinary system. We experienced a 51-year-old female with a left supernumerary kidney complaining microhematuria found by annual health checkups. Intravenous pyelography（IVP）revealed completely duplicated kidneys and ureters on the left side,confirmed by abdominal computed tomography（CT）,demonstrating a supernumerary kidney at the caudal and abdominal portion of the left normal kidney. On the cystoscopy,there were normal ureteral orifice on both sides and one extra orifice near left urethral meatus. The supernumerary kidney was not atrophic nor hydronephrotic,and was almost as normal as the major kidney. She is under observation at our clinic. This seems one of the rarest case reported in japan for the past 20 years,since most of the supernumerary kidneys reported in the past were atrophic,hydronephrotic or non functioning.