HISTOLOGIC MALDEVELOPMENT OF UNILATERALLY CRYPTORCHID TESTES AND THEIR DESCENDED PARTNERS

The pathogenesis of the increased incidence of subfertility in cryptor chidism remains controversial, and the concept that the prepubertal te stis is a quiescent organ continues to be held by some. Histomorphomet ric analyses including total and differential germ cell counts and Ley dig counts were performed on semithin sections of biopsies from 459 un ilateral undescended testes and 356 of their contralateral descended p artners in order to further investigate these two issues. The results demonstrate reduced numbers of Leydig cells, delayed disappearance of gonocytes, delayed appearance of adult dark spermatogonia, failure of primary spermatocytes to appear, and reduced total germ cell counts in the undescended testis. These findings support the hypothesis that un derstimulation of the testis leads to reduced numbers of Leydig cells which leads to delayed and defective maturation of germ cells and redu ced total germ cell counts which underlie the increased risk of subfer tility in cryptorchidism. The appearance of adult dark spermatogonia i n the first year of life and the onset of meiosis at three years of li fe in the contralateral descended testes contradicts the view that the prepubertal testis is quiescent. Complete evaluation of prepubertal t esticular biopsies should include total and differential germ cell cou nts and Levdig cell counts.