Cryptorchidism (Undescended Testis)

Risk factors

• Prematurity, low birth weight, small-for-gestational-age
• Family history of cryptorchidism
• Maternal smoking, exposure to endocrine-disrupting chemicals
• Genetic syndromes: Klinefelter, Prader-Willi, Kallmann, persistent mullerian duct syndrome, androgen insensitivity
• Disorders of sex development (DSD) — especially if bilateral non-palpable

Pathophysiology

Testicular descent occurs in two phases: trans-abdominal (mediated by INSL3/RXFP2) and inguinoscrotal (androgen-dependent, mediated by genitofemoral nerve and CGRP). Disruption of either step results in cryptorchidism.

Clinical presentation

Differential diagnosis

• Retractile testis — Hyperactive cremasteric reflex; testis can be manipulated into the scrotum and remains briefly — not cryptorchidism, no surgery needed but monitor (some become ascending testes)
• Ascending testis (acquired UDT) — Previously fully descended testis later found out of the scrotum — managed similarly to congenital UDT with orchiopexy
• Ectopic testis — Outside normal path of descent (perineal, femoral, contralateral scrotal); requires surgery
• Anorchia / vanishing testis — Non-palpable testis found absent at surgery (blind-ending spermatic vessels on laparoscopy); in unilateral cases AMH and testosterone are normal because the other testis functions; bilateral anorchia = undetectable AMH/inhibin B and no testosterone rise after hCG stimulation

Diagnostic workup

Diagnostic algorithm

flowchart TD
  A["Newborn male, empty scrotum"] --> B{"Bilateral<br/>non-palpable?"}
  B -->|Yes| K["Urgent DSD/CAH evaluation now<br/>karyotype, 17-OHP, electrolytes, AMH"]
  K --> E
  B -->|No| C["Observe to 6 mo<br/>(corrected age)"]
  C --> D{"Descended<br/>by 6 mo?"}
  D -->|Yes| R["Routine well-child care"]
  D -->|No| E["Refer to pediatric urology"]
  E --> F{"Palpable?"}
  F -->|Yes| G["Inguinal orchiopexy<br/>between 6-18 mo"]
  F -->|No| H["Diagnostic laparoscopy"]
  H -->|Intra-abdominal| I["Orchiopexy<br/>+/- Fowler-Stephens"]
  H -->|Absent / vanishing| J["Document, no further surgery"]

Treatment

Complications

• Subfertility/infertility (greater in bilateral, intra-abdominal, and late-corrected cases)
• Testicular germ cell cancer — RR ~2-8x for cryptorchid testes; orchiopexy reduces but does not eliminate risk and allows surveillance
• Testicular torsion (cryptorchid testes are at increased risk)
• Associated inguinal hernia (high incidence)
• Psychological impact

PANCE pearls

• Refer to pediatric urology by 6 months of age if testis has not descended — definitive surgery before 18 months reduces complications.
• Imaging is NOT useful in cryptorchidism — diagnostic laparoscopy is the gold standard for non-palpable testes.
• Bilateral non-palpable testes in a phenotypic male require urgent evaluation for disorder of sex development, including CAH (potentially virilized 46,XX female with salt-wasting crisis).
• Orchiopexy reduces but does not eliminate testicular cancer risk; lifelong self-examination education is recommended.
• A retractile testis is a normal variant and does not require surgery, but should be followed because a subset become ascending and require eventual repair.

References

• AUA 2014 — AUA Guideline: Evaluation and Treatment of Cryptorchidism (Kolon et al., J Urol 2014)
• EAU/ESPU — EAU/ESPU Guidelines on Paediatric Urology — Cryptorchidism