[Congenital prepubic sinus: etiology and therapy]

Congenital prepubic sinus (CPS) is a rare diagnosis. It is defined as a blind-ending tract originating from the midline of the genital region. There are three types of CPS classified according to the course of the tract and location of the skin opening. The etiology is thought to be an intussusception during fusion of the abdominal wall or, alternatively, incomplete urethral duplication.

We report on a two-year-old boy with a skin fistula on the dorsal side of the penis. A slight secretion occurred when the surrounding subcutaneous tissue was compressed. After total resection of the sinus, histological examination revealed that the tract was lined primarily with multilayered epithelium. Immunohistochemical studies showed that the sinus was lined with transitional and squamous epithelium. At the base the lining epithelium was transitional and shifted distally to noncornifying squamous epithelium. The epithelial layer therefore corresponded to the inner surface of the urethra, thus supporting the assumption that CPS results from incomplete urethral duplication.

The immunohistochemical examination of the epithelium of Type II CPS proved, in this case, the existence of urothelium as the inner surface of the sinus. In view of this evidence it appears likely that the congenital prepubic sinus can be classified etiologically as an incomplete urethral duplication.