A Histomorphological Study of the Divergent Corpus Spongiosum Surrounding the Urethral Plate in Hypospadias

Abstract

ObjectiveTo investigate the histomorphological changes of the divergent corpus spongiosum surrounding the urethral plate in hypospadias. MethodsSeventy boys with hypospadias were divided into the distal (n = 44) and proximal (n = 26) groups by the location of the ectopic meatus. The morphology of the divergent corpus spongiosum was evaluated and the histopathological studies were carried out by HE staining, Masson staining, and immunohistochemical analyses of α-SMA, CD34, TGF-β1 and androgen receptor. Western blotting was performed to measure the expression of TGF-β1 and androgen receptor. ResultsThe divergent corpus spongiosum was significantly thicker in the distal group than the proximal group (distal 3.14 ± 1.12 mm, proximal 1.74 ± 0.87 mm, P <.0001). Histological evaluation suggested the cavernous sinus in the hypospadias group had an abnormal structure, which was characterized by an increase in the width of the vascular lumen (control 7.20 ± 1.12 μm, hypospadias 13.75 ± 8.08 μm, P = .0068), an increased vascular wall thickness (control 5.40 ± 1.28 μm, hypospadias 14.11 ± 7.59 μm, P = .0006), a decreased vascular density (control 15.66 ± 1.17, hypospadias 7.24 ± 4.19, P <.0001) and a decreased trabecular density (control 9.80 ± 1.92, hypospadias 3.68 ± 2.87, P <.0001). The severity of the structural abnormalities was greater in the proximal group than the distal group. Immunohistochemical analysis and Western blotting showed decreased TGF-β1 and androgen receptor expression in the hypospadias group (P <.0001). ConclusionsHistomorphological analysis showed that the divergent corpus spongiosum in hypospadias is abnormal. The structural variation is positively correlated with the severity of hypospadias.