Cryptorchidism is one of the most common congenital anomalies in young boys. Typically, this asymptomatic condition presents during a routine well-child examination where 1 or both testicles are not palpable in the scrotum. Diagnosis depends on physical exam and ultrasound is performed only when other disorders are suspected. Treatment is dependent on patient age and testis position. In boys with persistent undescended testis by age 6 months, the condition is unlikely to spontaneously resolve. If the testis is palpable but not in the dependent intrascrotal location, an orchiopexy (bringing the testicle to the scrotum) is preferred. If the testis is non-palpable, a diagnostic laparoscopy is needed to inspect for an intra-abdominal testis, which requires a staged Fowler-Stephen’s orchiopexy.

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Cryptorchidism is the absence of 1 or both testicles in the scrotum. Cryptorchid testis (“hidden testis”) may be undescended or absent (atrophied).


  • Prevalence at birth about 3% overall: 
    • Full-term infants: 2%–5%  
    • Premature infants: 30% 
  • Risk factors:
    • Maternal smoking and alcohol exposure 
    • Fetal exposure to paracetamol/acetaminophen and diethylstilbestrol  
    • Prematurity 
    • Small for gestational age and low birth weight
  • Cryptorchidism is usually an isolated condition, but there are related disorders:
    • Disorders of sexual differentiation (DSD) 
    • Congenital adrenal hyperplasia (CAH) 
    • Genetic disorders such as Klinefelter syndrome and Prader-Willi syndrome


Pathogenesis overall is not well understood but is affected by hormonal and anatomical embryologic factors.

Normal mechanical descent:

  • Intra-abdominal phase: mediated by the hormone descendin
  • Inguinal phase (by the 28th week of gestation): mediated by androgen/testosterone 
  • Gubernaculum swells and pulls the testis down into the scrotum along the inguinal canal. 

Defective mechanisms in the different phases of descent:

  • Alterations in hypothalamic-pituitary-adrenal (HPA) axis, especially testosterone 
  • In utero, increased expression of estradiol in the placenta 
  • Testicular agenesis (from vascular compromise, causing absent testis)
  • Changes in abdominal pressure
Path of descent of the testis

Path of descent of the testis
A: normal path the testis follows as it descends into the scrotum
B: possible locations where an undescended testis can be found

Image by Lecturio.

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Clinical Presentation and Diagnosis

Clinical findings

  • Palpable: 
    • Suprascrotal (most common location): outside the external inguinal ring 
    • Intracanalicular: inguinal canal 
  • Non-palpable:
    • Intra-abdominal 
    • Absent testis 
    • Empty or hypoplastic scrotum


  • Diagnosis is mainly based on a comprehensive physical examination.
    • Testicular exam:
      • Position infant in the supine position.
      • Exam requires warm lubricated hands: 1 hand near the anterior superior iliac spine (ASIS) and the other on the scrotum
      • Use fingertips to sweep from ASIS along the inguinal canal.
    • Genital exam:
      • Assess position of urethral meatus to rule out hypospadias.
      • Check phallus for size and atypical appearance. 
      • Look for hypoplastic scrotum or poorly rugated scrotal skin. 
    • Inguinal exam: Assess for fullness; may indicate hernia or lymphadenopathy.
  • Imaging:
    • Generally not necessary as it lacks sensitivity or specificity on treatment decision
    • Ultrasound: may be indicated when ruling out disorder of sexual differentiation or gonads/uterus 


Treatment principles

  • Goal: Fix the viable undescended testis in the normal scrotal position or remove nonviable testicular elements.
  • Timing: 
    • No spontaneous descent by 6 months of age triggers the need for intervention.
    • Surgery before 2 years of age (ideally before 1 year) 
  • Treatment is recommended to:
    • Allow testicular growth and for fertility preservation
    • Reduce the risk of testicular cancer
    • Allow for detection of testicular masses
    • Decrease the risk of testicular torsion

Surgery for palpable testis

  • Orchiopexy via inguinal approach: Testis and spermatic cord are released from attachments and the testis is sutured in the scrotum. 
  • Complications: testicular atrophy, infection, bleeding, inguinal hernia

Surgery for nonpalpable testis

  • Diagnostic laparoscopy to search for intra-abdominal testis
  • If no testis is found, must determine presence of blind-ending vessels or testicular nubbin.
  • If testis is found, can proceed with laparoscopic orchiopexy (options):
    • Single-stage orchiopexy without division of gonadal vessels 
    • 1-stage Fowler-Stephens (FS) orchiopexy with gonadal vessels divided
    • 2-stage FS orchiopexy where the gonadal vessels are clipped to allow collateral blood flow to testis in 6 months to mobilize testis
Surgery for undescended testis

Surgical correction of undescended testis
Left: inguinal region dissection
Right: inguinal approach to orchiopexy with testicle exposed in inguinal canal

Image: “The practice of surgery” by Internet Archive Book Images. License: Public Domain

Clinical Relevance

  • Testicular cancer: Patients with a history of cryptorchidism have an increased risk of testicular cancer (relative risk of 2.9). The most common presentation is a painless testicular nodule. Most of the testicular cancers are germ cell tumors. Diagnosis involves physical exam, testicular ultrasound, serum tumor markers, and metastatic workup. Treatment is radical orchiectomy.  
  • Testicular torsion: the most common cause of acute testicular and scrotal emergency pain. Patients have unilateral testicular pain, most frequently caused by a high abnormal attachment of the tunica vaginalis, making it prone to twisting. Scrotal ultrasound is helpful, but testicular torsion is mostly a clinical diagnosis and requires immediate scrotal exploration and orchiopexy. 
  • Inguinal canal and hernias: hernia occurs in parts of the abdominal wall where the musculature is not continuous. The increased pressure in the abdominal cavity leads to an evagination (protrusion) of the parietal peritoneum and parts of organs through the surrounding muscles (in this case, the inguinal canal). Diagnosis is made by physical exam and ultrasound, with manual reduction or hernia repair as necessary. 
  • Infertility: A history of cryptorchidism will increase the incidence of impaired spermatogenesis and lower fertility rates. Studies show that early orchiopexy and diagnosis of undescended testis will lead to increased fertility preservation. 
  • Retractile testis: when the testicles are palpable but in an extra-scrotal position on examination and can be manipulated into the scrotum. The testicles will remain in a dependent scrotal location temporarily and re-ascend. Treatment is with serial exams and monitoring of descent. 


  1. Cooper, C.S. (2020). Undescended testes (cryptorchidism) in children: Management. UpToDate. Retrieved January 20, 2021, from
  2. Cooper, C.S. (2019). Undescended testes (cryptorchidism) in children: Clinical features and evaluation. UpToDate. Retrieved January 20, 2021, from
  3. Jacobs, Micah. (2020). Undescended Testis. AUA University: AUA Core Curriculum.
  4. Sickkids staff. (2010). Undescended testicle. Retrieved January 21, 2021, from

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