Cryptorchidism

Cryptorchidism is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • 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)

Epidemiology

Incidence
  • Predominant age: premature newborns
  • Predominant sex: male only

Prevalence
  • In the United States, cryptorchidism occurs in 1–3% of full-term and 15–30% of premature newborn males (2).
  • Spontaneous testicular descent occurs by age 1 to 3 months in 50–70% of full-term males with cryptorchidism.
  • Descent at 6 to 9 months of age is rare (1).

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.

Genetics
Occurrence of UDT in siblings as well as fathers suggests a genetic etiology.

Risk Factors

  • 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
  • Meningomyelocele
  • Hypospadias
  • Wilms tumor
  • Prader-Willi syndrome
  • Kallmann syndrome
  • Cystic fibrosis

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