Testicular biopsies may be performed as part of the diagnostic evaluation of the infertile man to describe spermatogenesis and to identify germ cell neoplasia in situ. Before biopsy sampling, assessment of semen quality and serum concentrations of reproductive hormones are performed, and the relationship between these parameters is well-described. However, the association between a given testicular histopathology and these parameters is not well-characterized, and we aimed to describe this association according to specific categories of testicular histopathology.
In total, 1400 men were grouped according to their testicular histopathology: complete spermatogenesis (n=977), reduced spermatogenesis (n=275), heterogeneous spermatogenic arrest (n=96), and homogeneous spermatogenic arrest (n=52). Immunohistochemistry (MAGE-A4, PIWIL1, TNP1) was used to identify spermatogonia, spermatocytes, and spermatids, respectively. Subsequent spermatogenic cell populations were quantified by image segmentation to describe the testicular histopathology. Data on semen quality and reproductive hormones were retrospectively evaluated as part of the clinical work-up.
A reduced number of spermatogonia was observed in the group with heterogeneous arrest compared to the complete spermatogenesis group. The spermatocyte and spermatid populations were also decreased; however, this was also observed in the groups with reduced and arrested spermatogenesis. Concentrations and total counts of sperm were reduced in the groups with reduced and arrested spermatogenesis compared to the complete spermatogenesis group, with the homogenous arrest group being the most severely affected. Compared to the complete spermatogenesis group, reproductive hormones in all groups showed significantly higher concentrations of FSH and LH and significantly lower concentrations of testosterone and inhibin B, with the heterogenous arrest group being the most severely affected.
Our data confirm the intimate relationship between testicular histopathology and semen quality and reproductive hormones showing the group with heterogeneous arrest have the most severe testicular dysfunction reflected by the lowest testosterone, highest LH and FSH, and decreased concentration and total counts of sperm.