Abnormal dartos fascia in buried penis and hypospadias: Evidence from histopathology.

INTRODUCTION

The importance of the pathology of the dartos fascia in hypospadias and buried penis is still debatable. Understanding the properties of connective tissue of dartos fascia in hypospadias and buried penis may give a clue to the underlying mechanism.

OBJECTIVE

This study aimed to compare connective tissue and vascularization of dartos fascia between normal penis, buried penis, and hypospadias.

STUDY DESIGN

We conducted this prospective study from May 2013 to November 2016. We collected dartos fascia specimens from three groups: buried penis, hypospadias, and normal penis as control. All of the patients underwent primary surgery in all groups. Patients with penile abnormalities, such as phimosis or Balanitis Xerotica Obliterans (BXO) were excluded from the normal penis group. We compared the fibers between these groups using Masson trichrome histochemical staining, Gomori's silver impregnation staining, Weigert resorcin-fuchsin staining, and CD31 immunohistochemistry staining for evaluation of collagen fibers, reticulin fibers, elastin fibers, and endothelial cells of blood vessels, respectively. The collagen fibers, reticular fibers, elastic fibers, and vascular vessels were counted with ImageJ and manually calibrated and counted and were analyzed using the one-way ANOVA test. The assessment conducted by two pathologists was blinded, without knowing the clinical diagnosis of patients.

RESULTS

There was a total of 60 patients with 20 patients in each group. Collagen fibers for most cases of buried penis and hypospadias showed thicker but fewer collagen fibers than the normal penis. There was a reduction of total collagen and elastin of dartos fascia in hypospadias and buried penis cases. On the other hand, the ratio of reticulin fibers, which represents collagen type III to total collagen, was increased compared to normal penis.

DISCUSSION

Although the dartos fascia in buried penis and hypospadias is thick and inelastic when palpated or during traction/counter traction, it is well-vascularized tissue. This inelastic dartos fascia tissue is an abnormal tissue, but its characteristics are not similar to fibrotic tissue. However, further study with a larger sample is warranted and should differentiate the degree of chordee in patients with hypospadias and buried penis.

CONCLUSIONS

There was a difference between connective the tissue of dartos fascia in buried penis and patients with hypospadias compared with normal penis. Inelastic dartos fascia tissue in patients diagnosed with buried penis and hypospadias is an abnormal tissue. Therefore, it is suggested that this tissue is excised during reconstructive surgery. Further research is needed to unveil the pathophysiology of the condition.