Differential expression of androgen and estrogen receptor of appendix testis in patients with descended and undescended testes

Objectives: The incidence of appendix testis has been shown to be 76% in descended and 24% in undescended testis in our previous intraoperative survey. To determine the possible role of the appendix testis in the process of testicular migration, we compared the androgen and estrogen receptor status of appendix testis in descended and undescended testes. Methods: Thirty-seven appendix testes were collected intraoperatively and the expression of androgen and estrogen receptors were examined with immunostaining and immunofluorescence labeling. Based on the diagnosis, the specimens were divided into three groups. Group H (groin hernia, n = 11, as a group of descended testis), Group AU (acquired undescended testis, n = 14), and Group CU (congenital undescended testis, n = 12). Results: The testicular appendages were found to express both androgen and estrogen receptors in Group H and Group AU, but specimens in Group CU were only estrogen receptor positive, whereas androgen receptors were not present. Conclusion: The presence of the androgen receptor in the appendix testis of the descended testes and acquired undescended testes and its absence in patients with congenital undescended testis suggests that the appendix testis might play a role in the process of testicular descent.