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- Incomplete or improper descent of one or both testicles; also called undescended testes (1)
- Normally, descent is in the 7th to 8th month of gestation. The cryptorchid testis may be palpable or nonpalpable.
- Types of cryptorchidism
- Abdominal: located inside the internal ring
- Canalicular: located between the internal and external rings
- Ectopic: located outside the normal path of testicular descent from abdominal cavity to scrotum; may be ectopic to perineum, femoral canal, superficial inguinal pouch (most common), suprapubic area, or opposite hemiscrotum
- Retractile: fully descended testis that moves freely between the scrotum and the groin
- Iatrogenic: Previously descended testis becomes undescended secondary to scar tissue after inguinal surgery, such as an inguinal hernia repair or hydrocelectomy.
- Also may be referred to as palpable versus nonpalpable (1)
- System(s) affected: reproductive
- Synonym(s): undescended testes (UDT)
- Predominant age: premature newborns
- Predominant sex: male only
Etiology and Pathophysiology
- Not fully known
- May involve alterations in
- Mechanical factors (gubernaculum, length of vas deferens and testicular vessels, groin anatomy, epididymis, cremasteric muscles, and abdominal pressure), hormonal factors (gonadotropin, testosterone, dihydrotestosterone, and müllerian-inhibiting substance [MIS]), and neural factors (ilioinguinal nerve and genitofemoral nerve)
- Major regulators of testicular descent from intra-abdominal location into the bottom of the scrotum are the Leydig cell–derived hormones, testosterone, and insulin-like growth factor 3 (IGF-3).
- Mutations in the gene for IGF-3 and in the androgen receptor gene have been evaluated as possible causes of cryptorchidism as well as chromosomal alterations (1).
- Environmental factors acting as endocrine disruptors of testicular descent also may contribute to the etiology of cryptorchidism.
- Risk of ascent may be as high as 32% in retractile testis.
Occurrence of UDT in siblings as well as fathers suggests a genetic etiology.
- Family history of cryptorchidism: highest risk if brother had UDT, followed by uncle and then father
- Low birth weight, prematurity, and small for gestational age are associated with a substantial increase in incidence of cryptorchidism (1). Retractile testes are at increased risk for ascent.
Commonly Associated Conditions
- Inguinal hernia/hydrocele
- Abnormalities of vas deferens and epididymis
- Intersex abnormalities
- Hypogonadotropic hypogonadism
- Germinal cell aplasia
- Prune-belly syndrome
- Wilms tumor
- Prader-Willi syndrome
- Kallmann syndrome
- Cystic fibrosis