Congenital absence of the testis in human fetuses and in cryptorchid patients

Background: The aim of the present study is to make a comparative study in human fetuses and in patients with cryptorchidism, analyzing the incidence of a number anomalies of the testes for both populations. Methods: We studied 326 testes from 163 human fetuses ranging in age from 10 to 35 weeks postconception (WPC) and 133 testes from 101 cryptorchid patients aged from 1 to 15 years old (mean, 6.4 years). The Fisher's exact test was used for comparison. Results: Among 326 fetal testes, 224 (68.7%) were abdominal, 45 (13.8%) were inguinal and 55 (16.8%) were scrotal. In one fetus at 23 WPC, both testes (0.6%) were absent. Of the 133 cryptorchid testes, 17 (12.78%) were abdominal, 92 (69.1%) were inguinal and 24 (18%) were high scrotal. Of the 17 abdominal testes, three (17.6%) were atrophic and two were vanished (11.7%). Of the 92 inguinal testes, one (1.08%) was vanished. Twenty-eight (21%) of the cryptorchid testes were impalpable and among these, 17 were located in the abdomen (60.7%) and 11 (38.2%) in the inguinal region (internal ring). Conclusions: Testicular agenesis is a very rare anomaly, both in fetuses and patients with cryptorchidism.