Cryptorchidism

• Cryptorchidism means one or both testes have not reached the scrotum: a normal testis can be felt at birth but its final stop is outside the scrotal sac.
• It is the commonest congenital anomaly of the male genital tract, and most testes that are undescended at birth either descend during the first three months or are unlikely to descend without help after six months.
• The problem is not cosmetic: an extrascrotal testis is exposed to higher temperature, risks hernia, torsion and trauma, and raises both infertility and testicular cancer risk.
• A retractile testis is a normal testis that simply retracts; it must be separated from a true undescended testis, because only the latter needs surgery.
• Surgery, usually orchidopexy, is ideally carried out between 6 and 18 months of age; hormonal treatment has limited effect and is not first-line. ^[1][5]

By the end of this page you should be able to:

1. Define cryptorchidism and distinguish a true undescended testis from a retractile, ascending, ectopic and vanished testis.
2. Explain the two phases of testicular descent and why an extrascrotal testis threatens germ cells and oncological safety.
3. Take a history and perform an examination that reliably separates true from retractile testes, including the cremasteric fatigue manoeuvre.
4. Plan investigations, knowing when ultrasound helps and when it does not, and when surgical exploration is the gold standard.
5. State the recommended age for orchidopexy and compare open and laparoscopic approaches, including for intra-abdominal testes. ^[5]
6. Counsel families on fertility and testicular cancer risk after surgery, including the role (if any) of hormonal therapy and long-term follow-up.

Cryptorchidism is therefore a description of position, not a single disease. It can be congenital (never descended), or acquired (previously in the scrotum then ascended), with different implications for surgery and counselling. About 10% of cases affect both sides, and bilateral cryptorchidism more often signals an underlying syndrome or a disorder of sex development. ^[2]

The commonest site for a palpable undescended testis is just outside the external inguinal ring (suprascrotal or prescrotal), then the inguinal canal itself, then the abdomen. In roughly one boy in five with cryptorchidism at least one testis is not palpable on examination. ^[2]

Cryptorchidism is the most common congenital anomaly of the male genital tract. Incidence is about 1–9% in full-term boys and up to 45% in premature infants; the prevalence in term infants falls to about 1% by one year of age as late spontaneous descent continues. Two Nordic cohorts found large geographical variation even between neighbouring countries: about 9% of newborn boys in Denmark versus about 2.4% in Finland, possibly reflecting genetic, environmental and definitional differences. ^{[2][1][5] [4]}

Prematurity and low birth weight (under 2.5 kg) are strong and consistent risk factors, and being small for gestational age adds risk on top of prematurity. Environmental exposures such as endocrine-disrupting chemicals, pesticides and phthalates have been linked in some, though not all, studies. ^[2]

Cryptorchidism is usually an isolated anomaly. When it occurs with other findings—especially bilateral non-palpable testes or hypospadias—it more often accompanies abdominal wall defects, neural tube defects, cerebral palsy, genetic syndromes (for example Klinefelter, Prader–Willi and chromosomal disorders) or differences in sex development. The coexistence of cryptorchidism and hypospadias in particular raises the probability of an underlying difference in sex development. ^[2]

Testicular descent has two phases. In the transabdominal phase (roughly weeks 8–15 of gestation) the gubernaculum swells and shortens under the influence of insulin-like 3 (INSL3), anchoring the testis in the inguinal region. In the inguinoscrotal phase (about weeks 25–35) androgens, the genitofemoral nerve and calcitonin gene-related peptide guide the testis into the scrotum. ^[2][3]

Failure is therefore multifactorial: abnormal hormonal signalling (low gonadotropins, low Müllerian-inhibiting substance, excess placental oestrogen), genetic and environmental factors, and intrauterine events such as prenatal torsion with vascular compromise. The same hormonal machinery explains why bilateral cryptorchidism and cryptorchidism with hypospadias point more often to a disorder of sex development. ^[2]

Acquired cryptorchidism is a separate entity: a testis that descended normally but later becomes extrascrotal because the spermatic cord fails to elongate with growth, or because of partial persistence of the processus vaginalis. Dutch schoolboys showed acquired undescended testes in 1.2% at age 6, 2.2% at age 9 and 1.1% at age 13, and in about two-thirds of such boys the testis had previously been documented in the scrotum. ^[5]

Everything that goes wrong follows from one fact: the scrotum is cooler than the abdomen, by about 2–4 degrees Celsius, because of the pampiniform plexus and the dartos. ^[3] A testis left outside the scrotum loses the temperature on which its germ cells depend.

The consequences accumulate with time:

• Germ cell loss. Prolonged exposure to higher temperature speeds germ cell apoptosis, blocks the transformation of gonocytes into adult dark (Ad) spermatogonia, and disturbs Sertoli cell maturation. Histological damage is sometimes present even in the contralateral, scrotal testis, which suggests that unilateral cryptorchidism can reflect bilateral testicular dysfunction rather than a purely local problem. ^[2][5][4]
• Fertility. Germ cell counts fall further with bilateral involvement and with longer residence in the suprascrotal or intra-abdominal position. Most studies show that Leydig cell function (testosterone production) is relatively preserved, so virilisation is usually normal even when sperm production is poor. ^[2]
• Malignancy. Testicular germ cell tumours are more common after cryptorchidism, and the risk is not abolished by moving the testis. Cryptorchidism is also the setting for germ cell neoplasia in situ, the precursor lesion. ^[2]
• Mechanical complications. An extrascrotal testis is more mobile and more readily twisted, and a higher or inguinal testis is more easily traumatised. Inguinal hernia or a patent processus vaginalis accompanies most undescended testes. ^[2]

Retractile testes deserve special attention because they are common, with a prevalence of about 1.2–3.9% in school-aged boys and bilateral involvement in roughly one-third. ^[3] They are not, by definition, an indication for surgery: the American Urological Association, the European Association of Urology/European Society for Paediatric Urology, the Nordic consensus and the Canadian Urological Association all recommend surveillance, with assessment at least annually and referral if ascent is documented. ^[3] A non-palpable testis raises a different question, because it may be intra-abdominal, ectopic, or absent. ^[2]

Most cases are found incidentally: a parent or clinician notices an empty hemiscrotum or asymmetry. A careful history prevents both missing a true undescended testis and operating on a retractile one:

• Position of the testes in the newborn period and during early well-child visits. Testes that were documented in the scrotum at birth favour retractility over congenital cryptorchidism.
• Age at first observation, and whether the testis has ever been seen or felt in the scrotum.
• Precipitating factors: cold, the inner-thigh stimulus, play, fear, tight clothing; whether the testis reappears when the child is asleep or in a warm bath.
• Laterality and any progression.
• Previous inguinal or scrotal surgery that might have created iatrogenic (scar-tethered) cryptorchidism.
• Maternal androgen exposure in pregnancy.
• Family history of cryptorchidism, retractility, hypospadias, infertility or unexplained neonatal death, which can signal a genetic or endocrinological condition. ^[2]

The environment matters: a warm room, warm hands and a relaxed child. The frog-leg or tailor's (cross-legged) position relaxes the cremaster. Inspect the scrotum for rugation, hypoplasia and asymmetry, and the inguinal region for fullness suggestive of a testis, hydrocele or hernia. ^[2]

Palpation uses two hands, starting at the anterior superior iliac spine and passing slowly along the inguinal canal toward the scrotum. For each palpable testis record position, size, consistency and mobility, comparing with the other side. Then attempt to bring the testis into the most dependent scrotum with gentle, sustained pressure. ^[2]

The single most useful bedside distinction is the cremasteric fatigue manoeuvre: hold the testis in the dependent scrotal position for at least one minute. A retractile testis tends to stay; a true undescended or ectopic testis does not. ^[2]

General examination is also important: dysmorphic features, midline defects, small phallus, hypospadias or bifid scrotum point toward a disorder of sex development or another syndrome. ^[2]

When a testis is palpable, look specifically for:

• a palpable "nubbin" or remnant, which may be atrophic tissue but can also be gubernaculum, epididymis or vas deferens and therefore does not exclude intra-abdominal testis; and
• contralateral testicular hypertrophy, which after puberty can suggest absence, though it never replaces exploration.

When no testis is palpable on either side, treat it as a different problem until a multidisciplinary team has excluded a life-threatening disorder of sex development. ^[2]

A common error is to confuse true undescended testis with four quite different entities. The distinguishing features are:

• Retractile testis — normally descended, slips up with cold or anxiety, can be brought down without tension and stays down at least briefly. ^[3]
• Gliding testis — high scrotal or at the external ring; can be brought down with traction but pops back immediately. Usually needs orchidopexy. ^[3]
• Ascending (acquired) testis — documented in the scrotum earlier, later found persistently extrascrotal with a short cord. Needs orchidopexy once ascent is confirmed. ^[3]
• Anorchia or vanishing testis — no palpable tissue; confirmed at exploration by blind-ending vessels. ^[2]
• Hydrocele or hernia alone — fullness present, but the testis itself is in the scrotum. ^[2]

Investigation is clinical. Imaging is not routine and should never delay referral.

• Ultrasound has poor sensitivity for non-palpable testes, roughly 45% with about 78% specificity in a systematic review, and is therefore not a substitute for exploration. ^[2]
• Ultrasound can be useful in selected circumstances: evaluating gonads and Müllerian structures in a phenotypic boy with bilateral non-palpable testes, where a disorder of sex development is possible, and assisting preoperative planning in an obese child where palpation is unreliable. Its accuracy for inguinal or scrotal testes is higher (about 92% pooled), but the underlying studies are heterogeneous. ^[2]
• Magnetic resonance imaging is occasionally used for intra-abdominal localisation but is rarely needed. ^[2]
• Hormonal evaluation and stimulation tests (hCG stimulation, inhibin B, Müllerian-inhibiting substance, gonadotropins, testosterone) are reserved for bilateral non-palpable or hypospadiac cases, to confirm the presence or function of testicular tissue before surgery. ^[2]
• Surgical exploration, usually laparoscopy for non-palpable cases, remains the gold standard: it localises the testis (or confirms absence) in almost 100% of cases. ^[2]
• Biopsy at operation is considered in selected cases, particularly for bilateral cryptorchidism, because histology predicts long-term fertility potential. ^[5]

The aim is to place each viable testis in the scrotum so that it can be examined for life, develops in cooler conditions and is protected from torsion and trauma. The concrete management decisions are timing, hernia repair and orchidopexy technique.

Consensus across major guidelines is early, not emergency, surgery once spontaneous descent has become unlikely:

• The European Association of Urology recommends orchidopexy between 6 and 12 months of age, and no later than 18 months. ^{[1][5] [4]}
• The American Urological Association recommends surgery between 6 and 18 months. ^[1][2][5]
• The Nordic consensus and the American Academy of Pediatrics (urology section) agree on the 6 to 18 month window. ^[4]

The biological rationale is that germ cells and Sertoli cells are already being lost while the testis stays extrascrotal, and early correction preserves germ-cell numbers and later fertility potential. Testicular descent is usually complete by three months; spontaneous descent after six months is rare, so a testis that is still undescended at six months of corrected age should be referred. ^[1][2]

delayed surgery is not benign. In a large population-based cohort, each six-month delay in orchidopexy increased later use of assisted reproduction by about 5% and reduced the paternity rate by about 1%. ^[4] In another cohort, each additional year of age increased the odds of postoperative testicular atrophy by about 29%. ^[1]

Orchidopexy relocates the testis and cord into the scrotum while preserving blood supply and ensuring tension-free fixation. Leaving hernias unrepaired is not an option: a patent processus vaginalis or inguinal hernia is present in about 90% of undescended testes, so hernia repair is done at the same time. ^[2]

For palpable inguinal or ectopic testes, primary open orchidopexy is the standard. It has a high success rate, about 96% in one systematic review, and a pooled postoperative testicular atrophy rate of about 1.8%. ^[2][5] Single-incision scrotal and two-incision inguinal approaches give similar outcomes, with the single-incision technique favoured for lower, longer-cord testes. ^[5]

For non-palpable and intra-abdominal testes, laparoscopy is now the standard approach: it establishes whether a viable testis exists, permits primary or staged orchidopexy, or removal of a non-viable remnant. When the spermatic vessels are too short for a one-stage repair, staged Fowler–Stephens procedures are used.

Gubernaculum-sparing second-stage techniques look promising because they preserve cremasteric vessels, but they are not yet embedded in all guidelines. ^[5]

Postoperative care is straightforward: restrict straddle activities for several weeks, review the wound at 1–2 weeks and testicular position and size at about 3 months. ^[2]

Hormones were once a mainstream treatment but are no longer first-line. The major guidelines (EAU, AUA, Nordic consensus) advise against using hormones as the primary treatment for undescended testes. ^[5]

The evidence is consistent with that position:

• Therapy with hCG or GnRH analogues has limited efficacy as monotherapy, with success generally below 20–30% overall, and a modest increase of around 10% in descent rates over placebo in a 2012 systematic review; individual study success ranged from 9% to 62%. ^[2]
• Response is better for distal (inguinal, prescrotal) than for intra-abdominal testes, and some apparent successes are probably retractile rather than truly undescended testes. ^[2]
• hCG and GnRH analogues appear similarly effective, with reported success between 6% and 35%. ^[2]
• Adverse effects include virilisation (penile enlargement, body hair, erections, behavioural changes) and, documented on the testis itself, interstitial bleeding and germ cell apoptosis. hCG in particular causes virilising effects more often (about 74%) than LHRH (about 5.1%). ^[2][5]
• There is no clear evidence that any agent, dose or schedule is superior, and no good evidence on cancer or fertility benefit. ^[2][5]

Some centres use hormones as an adjunct before surgery to try to bring a testis down, and selected investigators have explored postoperative GnRH in boys thought to have high infertility risk, but this is not standard care and requires larger trials. ^[5]

All guidelines stress long-term follow-up. ^[5] Practical follow-up has three layers:

1. Early postoperative: wound and position at 1–2 weeks, then a fuller assessment of size and position at 3 months. ^[2]
2. For boys with a retractile testis: structured re-examination every 6 to 12 months until puberty, documenting position, cord elasticity and (where available) testicular volume; referral or surgery if ascent, volume loss of at least 20%, cord tension, hernia, patent processus vaginalis or an episode of acute scrotum appears. ^[3]
3. Long-term: testicular self-examination from adolescence, and clear instructions about seeking care for a mass, pain or change.

Men with a history of cryptorchidism, including acquired undescended testes, more often have impaired spermatogenesis and reduced fertility compared with men whose testes descended normally, and bilateral disease is worse. ^[2][4]

• Semen studies show azoospermia more often after bilateral cryptorchidism, and oligospermia after unilateral disease. ^[4]
• In a long-term follow-up of men with childhood cryptorchidism, more than a quarter of an unselected azoospermic cohort (98 of 328) had a history of cryptorchidism. ^[4]
• Inhibin B and follicle-stimulating hormone (FSH) track Sertoli cell and tubular function: men operated before age two have higher inhibin B and lower FSH than those operated later. ^[2]
• Paternity is lower after bilateral than unilateral disease. One systematic review reported paternity rates of 14–89.7% after unilateral and 8–65.3% after bilateral cryptorchidism; the relative risk of infertility in the bilateral group was 5.3 in one cohort. ^[4]
• Age at surgery matters. The same review found no clear loss of fertility if orchidopexy was performed during childhood within the recommended window, but that continued delay carried cost: for every six months of delay the risk of needing assisted reproduction rose by about 5%. ^[4]
• Testicular sperm extraction (TESE or micro-TESE) can find sperm in men with azoospermia because testicular histology is heterogeneous, so biological fatherhood via assisted reproduction remains possible for many. ^[4]

Men with a history of cryptorchidism carry a substantially increased risk of testicular germ cell tumours compared with the general population, where the baseline age-adjusted incidence is about 5.4 per 100,000 males. ^[2]

• A 2013 meta-analysis (over 2 million boys) reported a pooled odds ratio of 2.9 for testicular cancer after cryptorchidism. ^[2]
• A 2023 meta-analysis of men who had surgery before adulthood reported an approximately fourfold increased risk. ^[2]
• Risk is higher with bilateral disease, intra-abdominal testes and associated endocrine or chromosomal abnormalities. ^[2]
• Age at orchidopexy matters: in a cohort of over 16,000 men operated on between 1964 and 1999, tumour incidence was 56 cases over about 210,000 person-years, with a relative risk of 5.4 in those operated at age 13 or older versus 2.2 in those operated before age 13. ^[2]
• Orchidopexy before puberty reduces, but does not eliminate, the risk. About 21% of tumours in men with unilateral cryptorchidism arise in the normally descended testis, showing that malposition is not the only cause. ^[2]
• Cancer surveillance should therefore continue after successful surgery, centred on education and self-examination rather than routine imaging. ^[2]

An undescended testis is associated with an increased risk of torsion and traumatic injury, particularly intracanalicular testes compressed against the pubic bone, and with inguinal hernia or patent processus vaginalis. ^[2] Retractile testes can also undergo torsion, though the evidence is limited to case reports and small series. ^[3]

After orchidopexy the commonest serious complication is atrophy, with a pooled incidence of about 1.8% in one review. Risk rises with non-palpable testes (about 3.35-fold higher risk than palpable), intra-abdominal position, comorbidities (the strongest factor, an eightfold increase in one series) and positive family history (about 2.7-fold). Delay adds risk on top. ^[1][2]

Prognosis is good when a child is referred and operated on in time. Early orchidopexy is associated with larger testicular volume, more spermatogonia per tubule and better inhibin B levels than late surgery, all of which indicate better future fertility. ^[5][2]

Poorer outcomes concentrate in boys with non-palpable or intra-abdominal testes, comorbidities, positive family history and late surgery. Bilateral involvement itself does not appear to add atrophy risk after surgery, but it does worsen fertility potential. ^[1]

• Every newborn should be examined for testes in the scrotum, including premature infants, whose testes usually descend as they mature. ^[5]
• Primary care should palpate the testes at every routine well-child visit, record position and symmetry, and take a careful gestational history. ^[2]
• If a testis is undescended at birth and has not descended by 6 months of corrected age, refer promptly to a surgical specialist. ^[2]
• Newly apparent (acquired) cryptorchidism after 6 months also warrants referral. ^[2]
• Education of parents about what a scrotum should feel like, and about regular self-examination once the boy is older, is the practical form of cancer screening available.

Bilateral non-palpable testes are a red flag. In a phenotypic boy they can indicate a disorder of sex development, including congenital adrenal hyperplasia, mixed gonadal dysgenesis or ovotesticular difference in sex development, which can be life-threatening in the neonatal period. These boys need urgent multidisciplinary assessment: karyotype, pelvic ultrasound for gonads and Müllerian structures, and hormonal testing (17-hydroxyprogesterone, testosterone, androstenedione, cortisol, gonadotropins, Müllerian-inhibiting substance), with electrolyte monitoring for salt-wasting. ^[2]

Even outside that emergency setting, bilateral undescended testes carry a higher cancer risk, higher infertility risk (relative risk 5.3 in one series) and lower inhibin B levels, so endocrine assessment and earlier follow-up are sensible. ^[2][4]

Undescended testes are much more common in premature boys and usually descend over the first months. The same referral rule applies: if a testis is still undescended at 6 months of corrected age, refer. ^[2]

Adolescents and adults found with an undescended testis should be assessed individually. Orchidopexy may still be appropriate for testicular and psychosocial reasons, but the cancer benefit of late surgery is smaller; some testes that are clearly non-viable are removed. ^[2][5]

• A careful two-handed examination with the child relaxed and warm is the whole diagnosis in most cases. Manoeuvres such as the cremasteric fatigue test cost nothing and are often more informative than requests for imaging.
• Ultrasound for non-palpable testes has low sensitivity and should not become the gatekeeper to surgery or to referral; when it is unavailable, refer on clinical grounds. ^[2]
• Where surgical or paediatric urology services are distant, refer early once spontaneous descent has been excluded; the timing matters more than the brand of hospital.
• Send every removed testis or remnant for histology when possible.

Children with undescended testes are often seen alongside children with hypospadias, inguinal hernia, testicular torsion and scrotal swelling; see those topics for shared examination and management principles. Disorders of sex development and paediatric endocrine conditions also need cross-reference. This page does not link those topics directly because they are separate MedGrasp entries.