一部自然排石により排尿障害をきたした前立腺結石

A case of prostatic calculi passage which caused voiding disorder

　症例は76歳，男性。排尿困難と尿道閉塞感を主訴に初診した。視診にて外尿道口に，KUBで前立腺部にそれぞれ結石を認め，嵌頓結石摘除と経尿道的砕石術を施行した。前立腺部には一部尿道粘膜を残し空洞が形成されていた。術後排尿状態は良好であった。結石成分はリン酸カルシウム75％，炭酸カルシウム25％で，前立腺結石の自然排石例と考えられた。比較的大きな前立腺結石を認めた場合は排尿状態なども考慮に入れた診察が必要と思われた。

A 76 year-old man presented with voiding difficulties and urethral pain. There were calculi at external meatus and at prostate on digital rectal examination and pelvic X-ray. He underwent meatotomy and transurethral extirpation of urethral and prostate stones. Endoscopically the prostate fossa was cavitated like as post-prostatectomy while partially the cavity was lining with urotherial mucosal bridge. Prostatic calculi were situated in the fossa. Postoperative voiding cystourethrography and retrograde urethrography showed that vesical neck function was competent,which was different from that seen after prostatectomy,and there was no functional and mechanical obstruction in the urethra. The calculi were made of calcium phosphate（75％）and calcium carbonate（25％）. This constitution is more common in prostatic calculus than urethral stone. Prostatic calculus per se does not cause lower urinary tract symptoms in most cases. However,we recommend the transurethral extirpation of large prostatic calculi which substantially cause lower urinary tract symptom.