Undescended

Undescended, commonly referred to in medical contexts as undescended testis or cryptorchidism, describes a condition in which one or both testicles fail to move from the abdomen into the scrotum before birth. The normal process of testicular descent occurs in two phases during fetal development; interruption of either phase can result in an undescended testis. The condition is the most frequent genital abnormality in newborn males, affecting approximately 2–4 % of full‑term infants and up to 30 % of premature infants. In most cases the testes descend spontaneously within the first few months of life; persistent undescended testes after six months typically warrant evaluation.

Etiology is multifactorial and may include hormonal deficiencies, anatomical abnormalities, genetic factors, or intra‑uterine pressures that impede normal migration. Diagnosis is usually made by physical examination; if the testis is not palpable, ultrasound or magnetic resonance imaging may be employed, though imaging is not always definitive.

Management aims to reduce risks of infertility, testicular cancer, torsion, and trauma. The standard treatment is orchiopexy, a surgical procedure that relocates the testis into the scrotum and secures it, ideally performed between six months and one year of age. Hormonal therapy with human chorionic gonadotropin or gonadotropin‑releasing hormone has limited and inconsistent success.

Prognosis after timely orchiopexy is generally favorable, with many individuals achieving normal fertility and a reduced cancer risk comparable to the general population. Ongoing surveillance of the relocated testis is recommended throughout life.