- Incomplete or improper descent of one or both testicles; also called undescended testes (1)
- Normally descent is in month 7 to 8 of gestation. The cryptorchid testis may be palpable or nonpalpable.
- Can be congenital or acquired
- Types of cryptorchidism
- Pre-scrotal: at or above scrotal inlet
- Abdominal: testis located inside the internal inguinal ring
- Canalicular: testis located between the internal and external inguinal rings
- Ectopic: located outside the normal path of testicular descent; 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 due to scar tissue after inguinal surgery.
- Also may be referred to as palpable versus nonpalpable (1)
- System(s) affected: reproductive
- Synonym(s): undescended testes (UDT)
- Predominant age: newborn, more common in premature newborns
- Predominant sex: male only
Etiology and Pathophysiology
- Not fully understood, 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), and neural factors (ilioinguinal nerve and genitofemoral nerve)
- Insulin-like growth factor 3 (IGF-3) or androgen receptor gene (1)
- Environmental factors acting as endocrine disruptors
- Major regulators of testicular descent are the Leydig cell–derived hormones, testosterone, and IGF-3.
- Risk of ascent as high as 32% in retractile testis
Increased risk of UDT in first-degree relatives suggests a genetic etiology.
Commonly Associated Conditions
- Anatomic anomalies: inguinal hernia/hydrocele, abnormalities of vas deferens and epididymis, hypospadias, meningomyelocele
- Endocrine disorders: intersex abnormalities, hypogonadotropic hypogonadism, germinal cell aplasia
- Genetic disorders: prune-belly syndrome, Prader-Willi syndrome, Kallmann syndrome, cystic fibrosis
- Wilms tumor
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