Dermoid sinus at the penis base: A congenital prepubic sinus

Introduction: Up to date, only six reports have been found in the literatur e on "congenital prepubic sinus" (CPS). The anatomy of this abnormality has been clearly defined: It is a fistula that proceeds from skin level above the symphysis directly at the penis base or above the clitoris and runs thr ough the pubic bone to end at the frond bladder or urethra wall. Its etiolo gy however has not yet been uncovered - an epispadial urethra with a blind end has been discussed as well as an intussusception during fusion of the a bdominal wall. Case Report: We report on a 13-month-old boy with an indefinite asymptomati c skin fistula at the penis base. Preoperative examinations (probing, X-ray ) revealed a ca. 15 mm long pseudofistula without bladder connection. The i ntraoperative situation showed that the sinus ran from the penis base deep inward and ended a few millimetres in front of the pubic bone. Histological examination revealed a squamous epithelial lining and several urothelial i slands at this depth. The surrounding connective tissue was of circular for mation. This was the first case of a "congenital prepubic sinus" where, des pite the missing connection to the bladder, urothelial islands were histolo gically determined. Conclusion: Our case supports the theory that CPS is a special form of wret hral duplication. The etiological possibilities of this rare congenital abn ormality are discused.