This review describes recent research into the cause of testicular descent and discusses two controversial theories on the mechanism. New animal models of cryptorchidism are described which shed light on the possible aetiology. A brief summary is given of current management, highlighting the controversies of timing of surgery, use of hormone therapy and congenital versus 'acquired' undescended testes. New information about germ cell development in the postnatal testis is changing the way we view treatment and the ultimate prognosis.

Autorentext

John M. Hutson, MD, DSc, has been Chair of Paediatric Surgery in the Department of Paediatrics, University of Melbourne, Australia since 2006 and is a former Director of General Surgery at the Royal Children's Hospital, Melbourne. Dr. Hutson has extensive clinical and research experience and has been the recipient of many awards during a career spanning four decades, including the Royal Australasian College of Surgeons Research Prize (2006), the Coe Medal from the Pacific Association of Pediatric Surgeons (2007), and the Sir Denis Browne Medal from the British Association of Paediatric Surgeons (2008). In 2004 Dr. Hutson accepted an Honorary Fellowship from the American Academy of Pediatrics (Surgical Section) and in 2007 he was made an Officer of the Order of Australia (AO). He has been Editor (Australasia) of Pediatric Surgery International since 2002 and Associate Editor of the Journal of Pediatric Surgery since 2003. His research has included detailed investigation into the regulation of testicular descent and disorders of sexual development. He is lead or co-author of more than 340 original papers in peer-reviewed journals and author or editor of 16 previous books, including Disorders of Sex Development: An integrated approach to management (Springer, 2012). Jørgen Thorup, MD, PhD, has been Head of the Department of Paediatric Surgery, Rigshospital, University Hospital of Copenhagen, Denmark since 1995 and Chair of Paediatric Surgery, Faculty of Health Science, University of Copenhagen, since 2006. Dr. Thorup is a Fellow of the European Board of Paediatric Surgery and of the European Academy of Paediatric Urology. He has been a member of the UEMS Joint Committee of Paediatric Urology (representative of the European Board of Paediatric Surgery) since 2003, and in 2011 became president of the committee. In 2014 he became an executive board member of the European Union Medical Specialists, Section of Paediatric Surgery. Dr. Thorup has been a speaker at numerous national and international congresses and is the author of more than 100 published articles as well as eight book chapters.

Inhalt
1 Introduction.- 2 Normal Testicular Descent.- 2.1 Two-Stage Hypothesis.- 2.2 Role of Müllerian Inhibiting Substance/Anti-Müllerian Hormone.- 2.3 Genitofemoral Nerve Hypothesis.- 2.4 Role of Calcitonin Gene-Related Peptide.- 2.5 Hypothesis to Explain Normal Testicular Descent.- 3 Cryptorchidism.- 3.1 Animal Models.- 3.2 Hypotheses of Aetiology.- 3.3 Recognizable Causes of Cryptorchidism.- 3.4 Congenital vs Acquired Cryptorchidism.- 3.5 Effects of Cryptorchidism.- 4 Management of Cryptorchidism.- 4.1 Rationale for Treatment and Its Timing.- 4.2 Surgical Treatment.- 4.3 Hormonal Treatment.- 4.4 Possible New Approaches to Treatment.- 5 Conclusions.- 6 References.- 7 Subject Index.