IS Case 92: Urethral Diverticulum
Imaging Sciences URMC 2008
Publication Date: 2009-05-20
A 47-year-old woman presents to her gynecologist with vaginal bleeding and urinary dribbling. She denied fevers, chills or other constitutional symptoms. No history of malignancy. She subsequently underwent cystoscopy, revealing a cyst-like structure arising from the urethra. The patient was then referred to Imaging Sciences for an MRI of the pelvis and a urethrogram for further evaluation.
MRI of the pelvis demonstrated a 2.5x 2.6cm cystic structure arising from the left aspect of the urethra, at the level of the pubic symphysis. T2 axial image shows elevated signal within the cyst (Fig. 1). Post-contrast fat-suppressed T1-weighted image demonstrates predominately low internal signal with minimal peripheral enhancement (Fig. 2). Sagittal T2-weighted image again demonstrates homogeneous elevated T2 signal and shows the relationship of the lesion, lying just below the bladder base (Fig. 3).
Retrograde, double-bubble urethrogram was then performed to further establish the connection between the lesion and the urethra. Fluoroscopic image during contrast injection demonstrates a contrast filled out-pouching of the left aspect of the urethra with a thin neck connecting the urethra lumen to the lesion (Fig. 4).
The female adult urethra is approximately 4 cm in length, extending from the bladder base to the vestibule. The urethra is lined by Skene's glands and the proximal wall is surrounding by two layers of smooth muscle, while the outer urethra is covered by striated muscle. Most female urethral diverticula are an acquired condition, seen in approximately 1.4 % of women with stress incontinence. They classically present clinically with dysuria, urinary dribbling, and dyspareunia. Large proximal diverticula may exhibit some mass effect on the bladder base similar to men with an enlarged prostate ("female prostate sign"). The diverticula may be simple or complex with multi-compartments and the neck may be wide or narrow. The neck typically arises from the urethra in a posterolateral configuration.
MRI and double-balloon urethrography as well as VCUG have all been effective in imaging this condition, with MRI reportedly having the highest sensitivity for detection. Complications of this disorder include frequent urinary tract infections, stone formation, and rarely malignant degeneration to adenocarcinoma, transitional cell carcinoma or squamous cell carcinoma.
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