[Physiopathology of the infertile testicle. Etiopathogenesis of varicocele].

To review current theories about etiology of varicocele and pathogenic mechanisms leading to a progressive disorder of spermatogenesis in relation to the subfertility or infertility these patients may present with. To evaluate its current anatomical knowledge of the normal venous drain of the testicle and its variations that may condition relapse or failure of the treatment of varicocele. To systematically review pathologic testicular lesions in patients with varicocele. To establish factors that may have prognostic significance on post-treatment fertility.We performed a systematic search in the Medline database for each of the proposed etiological and pathogenic theories on human varicocele. The evaluation of pathologic testicular lesions in patients with varicocele was obtained from the study of testicular biopsies performed at the Hospital La Paz in Madrid over the lost 30 years.Regarding the anatomical theories of varicocele, congenital absence or incompetence of the internal spermatic vein valves, difficult venous drain, augmented hydrostatic pressure of the internal spermatic vein, disorder of the fascial-muscular pump mechanism, and compression of the venous drainage system are considered, among others, potential etiological factors. Regarding possible pathogenic theories of varicocele, we evaluate disorders of testicular thermoregulation, hypoxia, toxic effect of renal and adrenal metabolites, certain endocrine disorders, obstruction of the spermatic tract, disorders of blood flow and epididymal vasculature, oxidative stress, gonadotoxins, apoptosis, and lastly the effect of varicocele on the contralateral testicle.Available data support the idea that etiopathogenesis of varicocele is multifactorial. Many classic etiopathogenic factors related to anatomy, embryology, obstruction, and hyperthermia still prevail in addition to new factors related to oxygen reactive species and apoptosis. However, many pathogenic and physiopathologic aspects of varicocele need to be elucidated yet. As a matter of fact, neither of these data alone may clearly explain the variable effect varicocele has on spermatogenesis and male fertility. So, it is necessary to establish histological criteria with proved prognostic significance that allow us to detect possible progression of testicular lesions after treatment.