The Relation between Adult Dark Spermatogonia and Other Parameters of Fertility Potential in Cryptorchid Testes

PurposeThe fertility potential of boys with cryptorchidism may be related to the number of adult dark spermatogonia per tubular transverse section in testicular biopsies taken at orchiopexy. Placental-like alkaline phosphatase positive gonocytes in testes within year 1 of life indicate preserved ability for germ cell transformation. We related these parameters to the total number of tubular germ cells and other factors associated with fertility potential.Materials and MethodsThe study comprised 89 boys 0.7 to 3 years old (median age 1.8) who underwent bilateral testicular biopsy at bilateral orchiopexy and provided blood samples for gonadotropins and inhibin B.ResultsOf 76 boys with adult dark spermatogonia 44 (58%) had a normal mean number of spermatogonia per tubular transverse section compared to 2 of 13 (15%) without adult dark spermatogonia (p <0.05). In the 30 boys with good fertility potential, including a normal mean number of tubular germ cells, and normal gonadotropins and inhibin B, the mean number of adult dark tubular germ cells was 0.081 vs 0.031 in the 38 with low fertility potential, including impaired tubular germ cells and/or low inhibin B but no reactive increase in gonadotropins (p <0.05). In the 21 patients with increased gonadotropins the mean number of adult dark spermatogonia per tubular transverse section was 0.063. Of the 20 boys with normal mean adult dark spermatogonia per tubular transverse section 12 (60%) had good fertility potential, including a normal mean number of tubular germ cells, normal gonadotropins and normal inhibin B, compared to only 18 of 69 (26%) with an impaired mean number of adult dark spermatogonia per tubular transverse section (p <0.05). Of 46 boys with a normal mean number of tubular germ cells 26 (57%) had placental-like alkaline phosphatase positive cells compared to 14 of 43 (33%) with a decreased mean number of tubular germ cells (p <0.05).ConclusionsThe number of placental-like alkaline phosphatase positive gonocytes and adult dark spermatogonia per tubular transverse section are important parameters related to the fertility potential of boys with cryptorchid testes.