Fig. 11.25 
A patient with the ‘vanishing testis’ syndrome. 
Such patients have evidence of hypogonadism, and no testicular tissue is found in the scrotum on surgical exploration. After hCG stimulation, testosterone levels do not rise. The term ‘vanishing testis’ derives from the presumption that testicular tissue was active in early foetal life in order to induce male phenotypic development. It is of unknown aetiology.