Cryptorchidism overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saumya Easaw, M.B.B.S.[2]
Overview
Cryptorchidism is the absence of one or both testes from the scrotum. This usually represents failure of the testis to move, or descend, during fetal development from an abdominal position, through the inguinal canal, into the ipsilateral scrotum. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis, making cryptorchidism the most common birth defect of male genitalia. However, most testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1% overall.
A testis absent from the normal scrotal position can be:
- found anywhere along the "path of descent" from high in the posterior (retroperitoneal) abdomen, just below the kidney, to the inguinal ring;
- found in the inguinal canal;
- ''ectopic'', that is, found to have "wandered" from that path, usually outside the inguinal canal and sometimes even under the skin of the thigh, the perineum, the opposite scrotum, and femoral canal;
- found to be undeveloped (hypoplastic) or severely abnormal (dysgenetic);
- found to have vanished (also see Anorchia).
About two thirds of cases without other abnormalities are unilateral; 1/3 involve both testes. In 90% of cases an undescended testis can be palpated (felt) in the inguinal canal; in a minority the testis or testes are in the abdomen or nonexistent (truly "hidden").
Undescended testes are associated with reduced fertility, increased risk of testicular germ cell tumors and psychological problems when the boy is grown. Undescended testes are also more susceptible to testicular torsion and infarction and inguinal hernias. To reduce these risks, undescended testes are usually brought into the scrotum in infancy by a surgical procedure called an orchiopexy.
Although cryptorchidism nearly always refers to congenital absence or maldescent, a testis observed in the scrotum in early infancy can occasionally "reascend" (move back up) into the inguinal canal. A testis which can readily move or be moved between the scrotum and canal is referred to as retractile.