Histopathological mapping of open testicular biopsies in patients with unobstructive azoospermia

To evaluate, in patients with unobstructive azoospermia, the heterogeneity of spermatogenesis within the testes and thus whether there is any region of advanced spermatogenesis. Patients and methods Seventy infertile men (mean age 34 years, SD 5.01) with no varicoceles or testicular atrophy had bilateral open testicular biopsies taken from six different sites. For each biopsy specimen the number of seminiferous tubules and of tubules with sperm maturation were counted (by light microscopy at x 400). The ratio of tubules with active spermatogenesis to the total number was calculated for each biopsy sample.

The mean (SD) right and left testicular volumes were 19.82 (7.8) and 18.84 (7.89) mL, respectively; the patients' follicle-stimulating hormone level was 8.34 (1.17) IU/mL. On sextant biopsy spermatozoa were detected in 42 of the 70 patients (60%). The mean (SD) ratio of tubules with spermatozoa was 5.23 (0.8)% for the right and 5.37 (0.76)% for the left testes. There was no statistically significant difference in the ratio of seminiferous tubules positive for spermatozoa at the different biopsy sites in either the right or left testis. Spermatozoa were identified in only one to three biopsy sites in almost half of those with maturation arrest; this ratio increased to 74% in patients diagnosed as having Sertoli-cell-only syndrome with focal spermatogenesis. Conclusion There is no region of the testis that is rich or advanced in spermatogenesis in patients with unobstructive azoospermia. Without multiple testicular biopsy it is possible to miss advanced spermatogenesis in some unobstructed patients. The sextant testis biopsy is a reliable method for detecting the presence and exact location of seminiferous tubules with spermatozoa in patients with unobstructive azoospermia.