title: Congenital prepubic sinus: a variant of dorsal urethral duplication suggested by immunohistochemical analysis.
abstract: OBJECTIVE
  Congenital prepubic sinus is a rare disorder of uncertain etiology. Immunohistochemical staining is used to elucidate the etiology of the sinus.
  
  
  METHODS
  We treated 5 patients with congenital prepubic sinus. A sinogram delineated the tract, which was then excised. In addition to routine hematoxylin and eosin stain of the 5 specimens, immunohistochemical analysis was also performed with smooth muscle and sarcomeric actin, high (34betaE12) and low molecular weight cytokeratin (35betaH11), and cytokeratin 7 antibodies.
  
  
  RESULTS
  The 2 females and 3 males were 1 month to 14 years old. All patients had presented with purulent discharge from the sinus opening. Hematoxylin and eosin stain demonstrated transitional and squamous epithelium lining the sinus. Immunohistochemical study showed that the stain with 3 cytokeratin antibodies was moderately to strongly positive in all patients at the proximal end, low molecular weight cytokeratin weakly to moderately positive and cytokeratin 7 weakly positive to negative in 4 at the distal end. The results suggested that the lining epithelium was transitional proximally and squamous distally. An exception was a female patient who had the shortest tract lined with squamous epithelium only. Furthermore, smooth muscle but not sarcomeric actin demonstrated smooth muscle bundles around the sinus tract in 4 patients.
  
  
  CONCLUSIONS
  The existence of transitional epithelium in the proximal part of the sinus and presence of smooth muscle bundles around it reinforce the theory that congenital prepubic sinus is a variant form of dorsal urethral duplication.
authors.affiliation: Department of Pathology, Chang Gung Memorial Hospital and Children's Hospital at Kaohsiung, Taiwan.
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
authors.forename: W H
authors.initials: WH
authors.lastname: Wu
authors.forename: C Y
authors.initials: CY
authors.lastname: Chai
authors.forename: T C
authors.initials: TC
authors.lastname: Wu
authors.forename: J H
authors.initials: JH
authors.lastname: Chuang
mesh_terms: D000293:Adolescent; D015415:Biomarkers; D004848:Epithelium / Q000473:pathology; D005260:Female; D005835:Genitalia / Q000002:abnormalities*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D053552:Keratin-7; D007633:Keratins / Q000276:immunology; D008297:Male; D014521:Urethra / Q000002:abnormalities*
chemical_list: D015415:Biomarkers; C507497:KRT7 protein, human; D053552:Keratin-7; D007633:Keratins