Unilaterally impalpable testis

Thirty children presenting with a unilateral impalpable testis and a normally descended contralateral testis underwent surgical exploration. The testis was absent ('vanishing testis') in 12 cases (40%) and orchidectomy for a dysgenetic testis was performed in a further 5 cases. The overall rate of monorchism following surgery was therefore 56%. It is desirable that parents be advised of this possibility pre-operatively.