A hypothesis to explain abnormal gonadal descent in persistent m�llerian duct syndrome

Abstract

Observations on the anatomy of patients with persistent mullerian duct syndrome (PMDS) shed considerable light on the causation of testicular descent. We present a hypothesis that explains the complex anatomical variants seen in this syndrome. The main anomaly (apart from persisting mullerian ducts) is failure of the gubernaculum to be masculinised, so that it remains long and thin, analogous to the round ligament. The mobility this gives the undescended testes accounts for apparent “descent” in some children, in whom the mobile testes have herniated into a patent processus vaginalis. Lack of gubernacular swelling in this syndrome supports a role for mullerian inhibiting substance or anti-mullerian hormone in the first phase of testicular descent.