Hypospadias, cryptorchidism and common male genital disorders: Viva

Branch 1: Confirming the diagnosis and separating the mimics

The candidate should state that the diagnosis of cryptorchidism is clinical and rests on a careful examination of the warm, relaxed child in the frog-leg or cross-legged squatting position, which relaxes the cremaster. [11] The examiner milks the testis down from the inguinal canal with one hand and palpates with the other, and a testis that can be brought into the scrotum but springs straight back out, or that cannot be brought down at all, is a true undescended testis. The stimulus case, in which the testis is palpable in the canal but cannot be brought to the scrotum, is a palpable undescended testis. [1]

If the examiner presses on the mimics, the candidate must distinguish the retractile testis, the ectopic testis, and the vanishing testis. The retractile testis is a normally descended testis pulled up by a brisk cremasteric reflex, and the defining test is that once milked into the scrotum it stays there without tension; this is a normal variant that needs follow-up rather than surgery. [11] The ectopic testis has descended through the external ring but come to rest in an abnormal location, and the vanishing testis is the result of prenatal vascular infarction. The retractile testis must be followed annually because up to a third ascend to become an acquired undescended testis. [11]

Branch 2: The management and the timing

If asked about management, the candidate should state that the palpable undescended testis is managed by surgical orchidopexy, and that the timing is the most important fact in the topic. [1] The testis that is still not in the scrotum at six months of corrected age will not descend spontaneously, so the American Urological Association and the European Association of Urology and European Society for Paediatric Urology guidelines both recommend orchidopexy between 6 and 18 months of age, ideally within the first year and no later than 18 months. [1] [2] The operation brings the testis out of the groin, mobilises the spermatic cord to gain length, and fixes it in a subdartos pouch in the scrotum. [3]

A strong candidate explains the biological rationale for the timing, because this is where the higher marks are earned. The undescended testis lies at a higher temperature than the scrotum, and this drives a progressive loss of the germ cells from the latter half of the first year of life. [4] Huff showed that the transforming spermatogonia and the adult dark spermatogonia, the stem cells of spermatogenesis, are progressively lost in the cryptorchid testis, so orchidopexy by 18 months brings the testis into the cooler scrotum before that germ-cell loss becomes irreversible. [4] [3]

Branch 3: Changing the scenario

If the examiner changes the scenario to a retractile testis, the candidate should state that the retractile testis is a normal variant that does not need surgery, because once milked into the scrotum it stays there. [11] The key follow-up point is that up to a third of retractile testes ascend over time and become an acquired undescended testis, so the retractile testis is reviewed annually until puberty and operated on if it ascends. [11]

If the examiner changes the scenario to a bilateral non-palpable testis, the candidate must recognise this as a disorder of sex development until proven otherwise. [2] The workup includes the karyotype, the electrolytes, the 17-hydroxyprogesterone, the testosterone, and the anti-Müllerian hormone, and a human chorionic gonadotrophin stimulation test distinguishes bilateral anorchia, in which there is no testosterone response, from functioning intra-abdominal testes. Laparoscopy localises the testes and allows orchidopexy or removal, and lifelong androgen replacement is planned for the boy with bilateral anorchia. The candidate should stress that the urgency is the exclusion of congenital adrenal hyperplasia, which may cause a salt-wasting adrenal crisis in the early weeks of life. [2]