[Case of lower urinary tract symptoms caused by urothelial papilloma-inverted type as diagnosed by transrectal ultrasonography at voiding].

A 54-year-old male visited our hospital, complaining of lower urinary tract symptoms (LUTS) such as loss of urinary force following the unsuccessful treatment using an alpha1-blocker. Transabdominal ultrasonography performed for measuring postvoid residual urine volume incidentally detected a solid tumor at the bladder neck. In addition, transrectal ultrasonography at voiding confirmed the tumor to obstruct prostatic urethra during voiding. Pathological diagnosis of the tumor resected transurethrally was urothelial papilloma-inverted type. Following the operation, LUTS improved markedly. Voiding TRUS was of clinical use for the definitive diagnosis of the etiology of LUTS.