{
 "topic": "Cryptorchidism",
 "slug": "cryptorchidism",
 "category_id": 15443,
 "summary": "Cryptorchidism terminology and classification, the DSD/CAH work-up in newborns with bilateral or hypospadias-associated cases, and the 6-18 month orchiopexy window for preserving fertility.",
 "written_by": "claude-sonnet",
 "references": [
  {
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 ],
 "short": [
  {
   "title": "In short",
   "content": "- Cryptorchidism means absence of one or both testes from the scrotum; it can be congenital (noted at birth) or acquired (\"testicular re-ascent,\" a previously descended testis found later in an extrascrotal position) - both must be distinguished from a retractile testis, which can be manipulated into the scrotum and stays there temporarily.\n- True undescended testis (UDT) is classified by location: abdominal, \"emergent\" (comes out of the internal ring and retracts back), intracanalicular (inguinal canal), or suprascrotal (just outside the external ring, the most common location) - the testis is nonpalpable in about 20% of UDT cases.\n- Congenital cryptorchidism occurs in about 1-4.6% of term males (over 2.5 kg), commonly cited around 2-4%, and in up to 30-33% of premature infants, reflecting that testicular descent normally occurs around 28 weeks' gestation.\n- About one-third to one-half of cryptorchid testes descend spontaneously, usually by around 3 months of age; spontaneous descent is very unlikely after 6 months (corrected age).\n- About 10% of cases are bilateral, and bilateral cases are more often associated with other conditions; unilateral UDT is more common on the left.\n- Fertility is impaired by about 33% after unilateral and about 66% after bilateral cryptorchidism; adult testicular cancer risk after childhood cryptorchidism is reported as 5-10 times normal, with histologic testicular changes demonstrable as early as 6 months of age in undescended testes.\n- Bilateral nonpalpable testes in a newborn should prompt evaluation for congenital adrenal hyperplasia (a virilized genetic female) before assuming a normal male; cryptorchidism with hypospadias (unilateral or bilateral, especially severe) may represent a disorder of sex development and needs karyotype and endocrine evaluation.\n- Hormonal therapy to induce descent is not recommended, as it has not shown proven long-term effectiveness. Congenital cryptorchidism is ideally corrected by orchiopexy between 6 and 18 months of age to best preserve spermatogenesis; when diagnosed later, orchiopexy before puberty still reduces future malignancy risk.\n- Ultrasound, CT, and MRI are not reliable for finding a nonpalpable (e.g., intra-abdominal) testis and are not indicated for this purpose; true congenital monorchism (absent testis with spermatic structures absent) can be associated with ipsilateral renal agenesis and warrants renal ultrasound, but an atrophied testis with spermatic structures present carries minimal such concern.\n"
  }
 ],
 "long": [
  {
   "title": "Definition",
   "content": "Cryptorchidism, by definition, is the absence of one or both testes from the scrotum. It may be congenital (present at birth) or acquired, also called testicular re-ascent, in which a testis previously documented in the scrotum is later found in an extrascrotal position. Both must be distinguished from a retractile testis, which moves easily in and out of the scrotum and can be manipulated into and held temporarily in a scrotal position. True undescended testis (UDT) is further classified by where along the normal descent pathway it has arrested: abdominal UDT (remains in the abdominal cavity), emergent UDT (exits the internal ring but returns to the abdomen), intracanalicular UDT (lodged in the inguinal canal), and suprascrotal UDT (just outside the external ring) - the last being the most common location, followed by the inguinal canal and then the intra-abdominal position. The testis cannot be palpated in about 20% of UDT cases.\n"
  },
  {
   "title": "Epidemiology",
   "content": "Congenital cryptorchidism occurs in roughly 1-4.6% of term males weighing more than 2.5 kg (commonly cited as 2-4%, or as high as 1 in 50), and in up to 30-33% of premature infants, since testicular descent through the inguinal canal into the scrotum normally occurs around 28 weeks' gestation. About one-third to one-half of cryptorchid testes descend spontaneously, usually by around 3 months of age, and gradual descent over several weeks is not unusual, particularly in premature infants. Because spontaneous descent beyond 6 months of corrected age is very unlikely, gestational age at birth is an important detail to record when tracking an infant with cryptorchidism. About 10% of cases are bilateral, and bilateral cryptorchidism is more commonly associated with other underlying conditions; when unilateral, the left side is more often affected.\n"
  },
  {
   "title": "Etiology",
   "content": "The cause of most cryptorchidism is not fully understood. It can occur in isolation or in association with abnormalities of the hypothalamic-pituitary-gonadal axis, intrinsic testicular developmental defects, or defects of androgen biosynthesis or receptor function. Cryptorchidism is associated with many syndromes but is rarely linked to urinary tract anomalies, with an important exception: true congenital monorchism (a genuinely absent testis, with no spermatic structures present) may be associated with ipsilateral renal agenesis, whereas in most cases of an \"absent\" testis, spermatic structures are actually present, indicating the testis formed but atrophied from a prenatal event - in these cases concern for renal agenesis is minimal. In older boys, a testis that was previously scrotal can \"ascend\" to a low inguinal position and require orchiopexy, and 1-2% of neonates and young males undergoing hernia repair develop secondary (acquired) cryptorchidism from scar tissue along the spermatic cord.\n"
  },
  {
   "title": "Clinical Features",
   "content": "Findings include an empty, hypoplastic, hypopigmented hemiscrotum with poorly developed rugae, sometimes with inguinal fullness if the testis is palpable in the canal. Patients with an undescended testis and hypospadias have a high incidence of an underlying disorder of sexual development (DSD), and this concern is especially significant when cryptorchidism (unilateral or bilateral) accompanies severe hypospadias.\n"
  },
  {
   "title": "Diagnostics",
   "content": "The diagnosis of bilateral cryptorchidism in an apparently normal male newborn should never be made without first considering that the infant could be a fully virilized genetic female with potentially fatal salt-wasting congenital adrenal hyperplasia (CAH); daily electrolyte monitoring is appropriate until salt-wasting CAH is excluded, and care must be taken to avoid premature gender/sex designation, birth certificate completion, or naming when a DSD is suspected. In infants 2-6 months of age, measuring LH, FSH, inhibin B, and testosterone can help determine whether functioning testes are present; after this age, an hCG stimulation test can confirm the presence or absence of functional abdominal testes. Ultrasonography, CT, and MRI can sometimes detect a testis in the inguinal region but are not reliably able to find an abdominal (nonpalpable) testis and are not indicated for this purpose. Hypospadias associated with even unilateral cryptorchidism should raise concern for an intersex condition, and karyotype should be obtained in the newborn. When true congenital monorchism is suspected (an actually absent testis with no spermatic remnant), renal ultrasound is indicated because of the association with ipsilateral renal agenesis.\n"
  },
  {
   "title": "Treatment",
   "content": "Hormonal therapy to induce testicular descent is not recommended, as it has not been shown to be effective long-term. Congenital cryptorchidism is ideally corrected surgically with orchiopexy between 6 and 18 months of age, to maximally preserve spermatogenesis; infants without spontaneous descent by 6 months of corrected age should be referred to an appropriate surgical specialist. When diagnosis occurs later, orchiopexy performed before puberty has been shown to reduce the future risk of testicular malignancy. Patients with a palpable testis are managed with an inguinal or scrotal orchiopexy approach, while those with a nonpalpable testis undergo a different (laparoscopic-based) surgical pathway.\n"
  },
  {
   "title": "Complications",
   "content": "Untreated cryptorchidism carries major long-term risks of infertility and testicular malignancy. Fertility is impaired by approximately 33% after unilateral cryptorchidism and approximately 66% after bilateral cryptorchidism. The risk of testicular cancer in adulthood after childhood cryptorchidism is reported as 5-10 times that of the general population, and histologic changes in the undescended testis are demonstrable as early as 6 months of age - underscoring the value of earlier rather than later surgical correction.\n"
  }
 ],
 "clinical": [
  {
   "title": "Newborn Evaluation of Cryptorchidism",
   "content": "Before labeling an apparently normal male newborn with bilateral cryptorchidism as such, actively consider that the infant could be a virilized genetic female with salt-wasting congenital adrenal hyperplasia - monitor electrolytes daily until this is excluded, and avoid premature gender assignment, naming, or birth certificate completion while the work-up is pending. In any newborn with cryptorchidism (unilateral or bilateral) accompanied by hypospadias, obtain a karyotype, since this combination carries a high risk of an underlying disorder of sex development, especially with severe hypospadias. Do not order ultrasound, CT, or MRI to search for a nonpalpable testis - these studies are unreliable for localizing an abdominal testis and are not indicated for this purpose; reserve renal ultrasound specifically for suspected true congenital monorchism (an absent testis without spermatic remnants), given its association with ipsilateral renal agenesis, which is not a concern when spermatic structures are present (indicating a prenatally atrophied rather than truly absent testis).\n"
  },
  {
   "title": "Timing of Referral and Surgery",
   "content": "Track gestational age and corrected age carefully: about one-third to one-half of cryptorchid testes descend spontaneously by about 3 months, but descent beyond 6 months of corrected age is very unlikely, so refer to a surgical specialist if descent has not occurred by then. Do not offer hormonal therapy to induce descent - it lacks proven long-term efficacy. Aim for orchiopexy between 6 and 18 months of age in congenital cryptorchidism to best preserve fertility potential; if a child presents later, still pursue orchiopexy before puberty, since this timing reduces (though does not eliminate) the increased future risk of testicular malignancy. Counsel families that even with correction, unilateral cryptorchidism is associated with roughly a 33% reduction in fertility and bilateral cryptorchidism with roughly a 66% reduction, and that adult testicular cancer risk remains elevated 5- to 10-fold compared with the general population - reinforcing the value of lifelong self-examination counseling as the child grows.\n"
  }
 ]
}