Pathological aspects of the infertile testis.

In this review, the pathological findings from testicular biopsies of men suffering from various types of infertility are presented. The causes of male infertility are divided into three major categories: pretesticular, testicular, and post-testicular causes. The pre-testicular causes of infertility may be defined as extra-gonadal endocrine disorders, such as those originating in the hypothalamus, pituitary, or adrenals, which have an adverse effect on spermatogenesis. The testicular causes of infertility are primary defects of the testes. The post-testicular causes of infertility consist primarily of obstructions of the ducts leading away from the testes. Cases in which the spermatozoa are normal in number but greatly impaired in motility, presumably due to faulty maturation or improper preservation of the spermatozoa during their sojourn in the epididymides, or due to biochemical abnormalities of the seminal plasma, are also included in the postesticular category.