We operated on a 12-year-old girl who had clitoromegaly and a sinus on the midline prepubic area congenitally. The prepubic sinus appeared to point to the clitoris on the preoperative magnetic resonance image, but the relation between the sinus and clitoromegaly was unclear. Gray-brown discharge was emitted at the site of dissection between the prepuce and clitoris and the size of the clitoris became normal. The sinus was excised, revealing a tract 1.5 cm long that extended to the retropubic sinus, and ended in a fibrous tract that was linked to the clitoris. This suggested pseudo-hypertrophy because of the discharge collected in the end of the prepubic sinus.