title: Congenital absence of the testis in human fetuses and in cryptorchid patients.
abstract: 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.
authors.affiliation: Urogenital Research Unit, State University of Rio de Janeiro, Rio de Janeiro, Avenue. 28 de Setembro, 87, fundos, FCM, térreo, 20551-030, Rio de Janeiro, RJ, Brazil. favorito@uerj.br
authors.forename: Luciano A
authors.initials: LA
authors.lastname: Favorito
authors.forename: Carlos Ab
authors.initials: CA
authors.lastname: Klojda
authors.forename: Francisco Jb
authors.initials: FJ
authors.lastname: Sampaio
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003456:Cryptorchidism / Q000150:complications / Q000196:embryology / Q000473:pathology*; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007223:Infant; D007264:Inguinal Canal / Q000473:pathology; D008297:Male; D012611:Scrotum / Q000473:pathology; D013737:Testis / Q000002:abnormalities* / Q000196:embryology