Subpubic Fistula: A Urethral Duplication

Abstract

The presence of prepubic and subpubic fistulas without other abnormalities is a rare variation in normal embryological development. These abnormalities are probably not associated with bladder exstrophy or a cloacal remnant but occur later with development of the genital tubercle. We report the identification of a subpubic fistula in a girl and subsequent evaluation, which give further insight into the embryology of this unusual entity. CASE REPORT An 8-year-old black girl presented for evaluation of enuresis. She had no history of urinary tract infections, and voided urinalysis and serum creatinine were normal. An opening was observed just superior to the clitoris (fig. 1). There was no discharge or local induration, and vaginal introitus and the female urethra were normal. Physical examination was otherwise unremarkable. The opening was probed for 1.5 cm. Renal ultrasound, excretory urography and dimercaptosuccinic acid scan were normal. At operation the fistula was dissected as it tracked just below and posterior to the pubic ramus for 3 cm., where it became a fibrous cord and could not be followed further or probed. Pathological evaluation of the cord revealed a soft tissue tract lined by squamous and probable transitional epithelium, which was surrounded by smooth muscle (fig. 2). DISCUSSION During early embryoloacal development the urinary tract and gut are joined at the cloaca. The normal genitourinary and gastrointestinal systems form as the anterior aspect of the cloacal membrane is closed by lateral mesodermal projections, and the urorectal septum separates the urinary and intestinal systems. The anterior aspect of the cloacal membrane can fail to close if the lateral mesodermal projections