[Total testicular regression syndrome or anorchidism].

Ten cases of boys without testis are presented. Clinical and anatomical patterns of the disease are analysed. Total absence of testicular tissue is proven by the lack of plasma testosterone response to HCG stimulation and by cautious surgical investigation. Artificial virilization by prolonged androgen administration associated with silastic prothesis implantation is the only possibility of treatment. Anorchism does not represent a form of gonadal dysgenesis or sexual ambiguity since external genitalia are always non ambiguous, chromosomal constitution is XY without any structural anomaly of Y and H-Y histocompatibility antigen is present. Absence or destruction of the testis are caused by different mechanisms, according to the data obtained by individual case studies. The most likely is that foetal testes developped normally are destroyed in utero or in the perinatal period or even soon after birth. The most frequent mechanism with a genetic predisposition, seems to be bilateral pedicle twisting.