New insights into the morphological and hormonal characteristics of spermatogenic arrest

The reported sperm retrieval rate (SRR) in patients with nonobstructive azoospermia (NOA) due to spermatogenic arrest (SA) is highly variable in the literature. This discrepancy could be explained by the heterogeneity of testicular tissues. Surprisingly, even though inhibin B levels reflect directly Sertoli cell function; no studies have evaluated this parameter in SA. We aimed to clarify the morphological and biological profile in 158 men with SA. From the total population, patients whose seminiferous tubules diameter was below 165 µm have higher SRR (46.9% vs. 27.4%, p < 0.05), lower inhibin levels and a higher frequency of nonuniform SA (71.9% vs. 38.7%, p < 0.001). On multivariate analysis, patients with late SA and a history of cryptorchidism were positively associated with successful sperm extraction. Patients with successful SRR and uniform SA exhibited inhibin levels twofold lower than those with failed TESE (45 pg/ml vs. 95 pg/ml, p < 0.05), whereas FSH levels were similar in the two groups. In this study, we showed for the first time that the mean diameter of the seminiferous tubules may be of value in the diagnosis of SA. Our results suggest that inhibin levels could be useful in the management of NOA with SA, along with FSH levels and testicular volume.