Cryptorchidism affects about 3% of term infants and up to 30% of preterm infants Preterm Infants An infant born before 37 weeks of gestation is considered preterm. In 2021 in the United States, 10.48% of births were preterm ( 1), and in 2018, 26.53% of births were early term (significantly... read more . About 10% of cases are bilateral. Two thirds of undescended testes spontaneously descend within the first 4 months of life. Thus, about 0.8% of male infants require treatment.
Eighty percent of undescended testes are diagnosed at birth. The remainder are diagnosed during childhood or early adolescence; these are usually caused by an ectopic gubernacular attachment and become apparent after a somatic growth spurt.
Pathophysiology of Cryptorchidism
Normally, the testes develop at 7 to 8 weeks gestation and remain cephalad to the internal inguinal ring until about 28 weeks, when they begin their descent into the scrotum guided by condensed mesenchyme (the gubernaculum). Onset of descent is mediated by hormonal (eg, androgens, mullerian-inhibiting factor), physical (eg, gubernacular regression, intra-abdominal pressure), and environmental (eg, maternal exposure to estrogenic or antiandrogenic substances) factors.
A true undescended testis remains in the inguinal canal along the path of descent or is less commonly present in the abdominal cavity or retroperitoneum. An ectopic testis is one that descends normally through the external ring but diverts to an abnormal location and lies outside the normal course of descent (eg, suprapubically, in the superficial inguinal pouch, within the perineum, or along the inner aspect of the thigh).
Complications of cryptorchidism
Undescended testes may cause subfertility and are associated with testicular carcinoma Testicular Cancer Testicular cancer begins as a scrotal mass, which is usually not painful. Diagnosis is by ultrasonography. Treatment is with orchiectomy and sometimes lymph node dissection, radiation therapy... read more , mainly in the undescended testis and particularly with intra-abdominal malposition. However, in patients with one undescended testis, 10% of cancers develop on the normal side. In untreated cases of intra-abdominal testes, testicular torsion Testicular Torsion Testicular torsion is an emergency condition due to rotation of the testis and consequent strangulation of its blood supply. Symptoms are acute scrotal pain and swelling, nausea, and vomiting... read more may occur, manifesting as an acute abdomen. Almost all neonates who present with an undescended testis at birth also have an inguinal hernia Inguinal Hernia in Neonates Inguinal hernias develop most often in male neonates, particularly if they are preterm (in which case the incidence is about 10%). The right side is affected most commonly, and about 10% of... read more (patent processus).
Etiology of Cryptorchidism
Undescended testes are almost always idiopathic. In phenotypic boys with bilateral, nonpalpable testes at birth suspicion should be high for female virilization caused by congenital adrenal hyperplasia Overview of Congenital Adrenal Hyperplasia Congenital adrenal hyperplasia is a group of genetic disorders, each characterized by inadequate synthesis of cortisol, aldosterone, or both. In the most common forms, accumulated hormone precursors... read more (especially if there is also hypospadias Hypospadias Congenital anomalies of the urethra in boys usually involve anatomic abnormalities of the penis and vice versa. In girls, urethral anomalies may exist without other external genital abnormalities... read more ).
Symptoms and Signs of Cryptorchidism
In about 80% of cases, the scrotum on the affected side is empty at birth; in the remainder of cases, a testis is palpable in the scrotum at birth but appears to ascend with linear growth because of an ectopic gubernacular attachment that restrains it from following the normal “descent” of the scrotum. Inguinal hernia associated with cryptorchidism is rarely symptomatic, but the patent process is often detectable, especially in infants (but less commonly in those with ectopic undescended testes). Rarely, an undescended testis manifests acutely because of testicular torsion.
Diagnosis of Cryptorchidism
Rarely ultrasonography or MRI
All boys should have a testicular examination at birth and annually thereafter to assess testicular location and growth.
Undescended and ectopic testes must be distinguished from hypermobile (retractile) testes, which are present in the scrotum but easily retract into the inguinal canal via the cremasteric reflex. Diagnosis of cryptorchidism is by physical examination; a warm environment, warm examiner’s hands, and a relaxed patient are important to avoid stimulating testicular retraction. If needed, the child can be placed in a frog-leg position to better examine the testes. Lubricating the child's groin or the examiner's gloved hands with soap before the examination can help decrease friction and aid in the localization of the testis.
In patients with a unilateral nonpalpable testis, a descended testis that is larger than expected suggests an atrophic undescended testis; confirmation requires surgical intervention typically via diagnostic laparoscopy to seek an intra-abdominal testis or confirm testicular agenesis. However, scrotal or inguinal exploration is sometimes done if a testicular remnant distal to the internal inguinal ring is suspected.
For bilateral nonpalpable testes, patients in the immediate neonatal period should be evaluated for a possible disorder of sexual differentiation (consultation with a pediatric endocrinologist should be considered). If a disorder of sexual differentiation has been ruled out, laparoscopy is often necessary to identify testes located in the abdomen and then bilateral orchiopexy may be done.
Treatment of Cryptorchidism
For a palpable undescended testis, treatment is surgical orchiopexy, in which the testis is brought into the scrotum and sutured into place; an associated inguinal hernia is repaired if present.
For a nonpalpable undescended testis, abdominal laparoscopy is done; if the testis is present, it is moved into the scrotum. If it is atrophic (usually the result of prenatal testicular torsion), the tissue is removed.
Surgery should be done at about 6 months of age in term infants and at 1 year of age in preterm infants because early intervention improves fertility potential and may reduce cancer risk. Also, the shorter the child, the shorter the distance necessary to place the testis into the scrotum.
No intervention is needed for a retractile testis as long as the spermatic cord length is sufficient to allow the testis to rest in a dependent scrotal position without traction when the cremasteric reflex is not stimulated. Hypermobility usually resolves without treatment by puberty when increased testicular size makes retraction more difficult.
Cryptorchidism affects about 3% of term infants and up to 30% of preterm infants; two thirds of undescended testes descend spontaneously.
Undescended testes may cause subfertility and increase risk of testicular carcinoma (including in the descended testis).
Clinical evaluation is usually adequate; imaging is rarely indicated.
Treatment is surgical repair.