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Cryptorchidism

Basics

  • Failure of one or both testes to descend properly into the scrotum
  • Types:
  • Prescrotal (at/above scrotal inlet)
  • Abdominal (inside internal inguinal ring)
  • Canalicular (between internal/external inguinal rings)
  • Ectopic (outside normal path: perineum, femoral canal, superficial inguinal pouch, suprapubic, contralateral hemiscrotum)
  • Retractile (normal descent but moves between scrotum/groin)
  • Iatrogenic (due to scarring after inguinal surgery)
  • Palpable vs nonpalpable testes

Epidemiology

  • Incidence:
  • 1-3% in full-term newborn males
  • 15-30% in premature newborn males
  • Spontaneous descent in 50-70% by 1-3 months in full-term infants
  • Descent beyond 6-9 months is rare

Etiology and Pathophysiology

  • Multifactorial:
  • Mechanical factors: gubernaculum, vas deferens/testicular vessel length, cremasteric muscle, groin anatomy
  • Hormonal factors: gonadotropins, testosterone, dihydrotestosterone, müllerian-inhibiting substance, IGF-3
  • Neural factors: ilioinguinal and genitofemoral nerves
  • Environmental endocrine disruptors
  • Genetic predisposition evidenced by family history
  • Risk of ascent (in retractile testes) ~32%

Risk Factors

  • Family history (brother > uncle > father)
  • Low birth weight, prematurity, small for gestational age
  • Maternal smoking, diabetes
  • Retractile testes at risk for ascent

Associated Conditions

  • Anatomic: inguinal hernia/hydrocele, vas deferens/epididymis abnormalities, hypospadias, meningomyelocele
  • Endocrine: intersex, hypogonadotropic hypogonadism, germinal cell aplasia
  • Genetic syndromes: Prune-belly, Prader-Willi, Kallmann, cystic fibrosis
  • Wilms tumor

Diagnosis

  • History: absence of ≥1 testicle in scrotum
  • Physical Exam:
  • Warm hands, examine in sitting, standing, squatting
  • Valsalva and abdominal pressure to identify gliding testes
  • Nonpalpable testis suggests intra-abdominal or atrophic
  • Enlarged contralateral testis suggests atrophy/absence of other testis
  • Differential: retractile testis, atrophic testis, vanished testis (in utero torsion or absent development)

Diagnostic Tests

  • Usually no labs/imaging if single testis nonpalpable in normal male
  • In bilateral nonpalpable testes >3 months, assess hormones (LH, FSH, MIS, testosterone), electrolytes, karyotype for sexual development disorders
  • Ultrasound and imaging generally not recommended; do not delay referral
  • Laparoscopy confirms presence and feasibility of orchidopexy in nonpalpable testes

Treatment

  • Rule out retractile testis first
  • Hormonal therapy not recommended due to low efficacy and lack of evidence
  • Referral to urology if no descent by 6 months corrected gestational age or newly diagnosed after 6 months
  • Surgery (orchidopexy) recommended before 1 year of age to reduce malignancy and infertility risks
  • Palpable testes approached via inguinal incision; laparoscopy for nonpalpable

Ongoing Care

  • Follow-up within 1 month post-surgery and periodically for testicular growth assessment
  • Annual exams for retractile testes to monitor ascent
  • Teach testicular self-exam at puberty due to increased tumor risk

Patient Education

  • Explain condition, treatment rationale, reproductive potential, and increased cancer risk
  • Early surgery improves outcomes; absent testis or orchiectomy may warrant prosthesis placement

Prognosis

  • Usually corrected surgically with good outcomes
  • Unilateral UDT paternity rates similar to general population
  • Bilateral UDT associated with reduced fertility (33-65%)
  • Contralateral testis may also have abnormalities

Complications

  • Infertility (especially bilateral)
  • Increased testicular cancer risk
  • Possible damage to contralateral testis

ICD10: - Q53.9 Undescended testicle, unspecified - Q53.20 Undescended testicle, unspecified, bilateral - Q53.10 Unspecified undescended testicle, unilateral

Clinical Pearls: - Testicular descent after 6 months is unlikely; refer to urology promptly at 6 months - Bilateral nonpalpable testes require hormonal and genetic evaluation - Imaging not recommended in initial evaluation - Bilateral UDT increases infertility risk