Two- and 3-dimensional ultrasonography in acute urinary retention due to distal urethral obstruction by infiltrating metastatic colon cancer

The management of urethral obstruction depends on its pathogenesis, which can be anatomic or functional. Localization of the site of anatomic urethral obstruction usually requires some invasive procedures.^1,2 Ultrasonography has been reported to be a noninvasive method of evaluating voiding disorders originating in the female urethra.^3-10 We report the ultrasonographic manifestations of a woman with voiding difficulty and acute urinary retention secondary to infiltrating metastatic rectal cancer. Vaginal ultrasonography with 3-dimensional (3D) scanning and Doppler flow angiography clearly showed obliteration of the distal urethra by an infiltrating tumor. A 3D axial view revealed poorly demarcated echogenic streaks in the normally anechoic portion of the urethra. These imaging results were sufficient to indicate the need for a suprapubic cystostomy to relieve the patient's urinary retention. She was thus spared more invasive diagnostic procedures. We suggest that vaginal ultrasonographic scanning of the lower urinary tract may serve as an initial workup for women with voiding dysfunction.