Signs and symptoms of undescended testicles include the following:

Infertility

Men with undescended testes may have reduced fertility, even after orchiopexy. [4]

• About 10% of unilateral cryptorchid testicle patients will develop infertilty.
• The reduction in fertility after orchiopexy for bilateral cryptorchidism is about 38%.
• This is the basis for the universal recommendation for early surgery due to degeneration of spermatogenic tissue and reduced spermatogonia counts after the second year of life in patients with untreated, undescended testes.

Psychological Consequences

Boys with undescended testicles do not tend to be effeminate, gender-disordered, or pre-homosexual. A disturbed self-image may occur when the family dynamics are destructive toward male self-esteem. When cryptorchism is surgically corrected, a healthy masculinity generally occurs. 

Cancer

Overall, the risk of testicular cancer if orchiopexy is done before puberty is about 3 times that of the general population. It is 5 to 6 times higher when orchiopexy is done after puberty. The risk of cancer does not seem to be different when orchiopexy is done early in infancy compared to later in childhood. [4]

• The most common type of testicular cancer in untreated undescended testes is seminoma. 
• The peak age range for this tumor is 15 to 45 years.
• In contrast, after orchiopexy, seminomas represent only 30% of testicular tumors in previously undescended testes.
• Testicular cancer is quite treatable if caught early, so boys who had an orchiopexy as infants should be taught testicular self-examination to assist with the early detection of cancer.
• Self-examination is particularly important for all males with a history of undescended testes starting right after puberty.

From the AUA Guidelines: “In the hands of an experienced provider, more than 70% of cryptorchid testes are palpable by physical examination and need no imaging. In the remaining 30% of cases with a nonpalpable testis, the challenge is to confirm absence or presence of the testis and to identify the location of the viable nonpalpable testis." 

Ultrasound is non-contributory in routine use, with sensitivity and specificity to localize nonpalpable testes reported at 45% and 78%, respectively. The cost and ionizing radiation exposure associated with CT scanning preclude its use. MRI with or without angiography has been more widely used with greater sensitivity and specificity but is discouraged due to its cost, low availability, and the need for anesthesia. At this time, there is no radiological test that can conclude, with 100% accuracy and reliability, that a testis is absent; "...regardless of preoperative radiological findings, these studies rarely assist in the decision making and may at times yield misleading information (such as absence when actually present or vice versa).” [5]

A karyotype can confirm or exclude dysgenetic primary hypogonadism. Hormone levels such as gonadotropins and Anti-Mullerian Hormone (AMH) may confirm hormonally functional testicles worth salvation, as can stimulation with human chorionic gonadotropin to elicit a rise in the testosterone level. In some cases, further testing is crucial and has a high likelihood of detecting intersex conditions. [4]

Medical Treatment

The AUA Guidelines state: "Providers should not use hormonal therapy to induce testicular descent as evidence shows low response rates and lack of evidence for long-term efficacy."

The American Pediatric Association Guidelines do recommend the use of hormones for cases of undescended testis associated with Prader-Willi Syndrome. Their reasoning is that a therapeutic trial of human chorionic gonadotropin (HCG) is indicated for treatment of undescended testes before surgery, because avoidance of general anesthesia is desirable for infants with low muscle tone and at high risk for underlying respiratory compromise.

• The most commonly used hormone is human chorionic gonadotropin (HCG). A series of HCG injections is given, and the status of the undescended testicle is reassessed. The success rate is reported as 5% to 50%. 
• Hormone treatment also will confirm Leydig cell responsiveness and induce additional growth of a small penis due to a rise in testosterone levels. 

The cost of hormone treatment is less than surgery, and the chance of complications are minimal. However, a recent meta-analysis of seven randomized clinical trials concluded that hormonal therapy was no more effective than placebo. [6]

Surgery

Surgery is recommended for congenital undescended testes between the ages of 6 and 18 months (AUA Guidelines). Many experts are recommending surgery early, at around 6 months, to optimize testicular growth and fertility. For premature babies, corrected age is used to determine surgery timing. Fertility is improved if the orchidopexy is performed early. Patients with bilateral undescended testes who receive orchidopexies as adults are almost always infertile and azoospermic; but there are now a few anecdotal reports of pregnancies achieved through assisted reproduction in this group. [7]

For acquired (testis documented normal before diagnosis) and entrapped (after hernia repair) undescended testes, surgery is recommended shortly after diagnosis. 

For retractile testes, a yearly physical examination is recommended because of the 2% to 50% reported risk of a retractile testis becoming an acquired undescended testis. 

Technique of Orchiopexy

For palpable undescended testes, an inguinal or scrotal orchiopexy is recommended. [7]

1. An incision is made in the high scrotum, median scrotal raphe, high edge of the scrotum, or groin. Many different type of retractors can be used depending of the size of the incision. Inguinal incisions can be as small as 1 cm. Scrotal incisions can be larger as they tend to heal concealed specially when in the median raphe. 
2. The testis can be approached first or the cord first; for scrotal cases, the testis is found first. For an inguinal approach, the testis can be approached first or the external oblique fascia opened proximal to the external ring and the cord approached first. 
3. When approaching the testis first, all the cremasteric muscles are divided as well as everything not going into the external ring.
4. The more difficult part of the case is separating the hernia sac from the vas and testicular vessels. This can be approached anteriorly or posteriorly. The posterior approach is much easier to teach and learn.
5. How the testis is positioned and secured in the scrotum varies. Most would agree that a sub-dartos pouch is desirable. Some surgeons do not suture the testis in place, others use absorbable sutures, others non-absorbable, and others just close the passage into the groin. 

For nonpalpable testes under anesthesia, exploratory laparoscopy is recommended. If a testis is found during exploratory laparoscopy, the options are: [7]

1. Laparoscopic orchiopexy preserving the vessels: the testis is dissected off a triangular pedicle containing the gonadal vessels and the vas.
2. Laparoscopic one stage Fowler Stevens (FS) orchiopexy: gonadal vessels are divided and the testis is dissected off a pedicle of the vas and brought down in one stage.
3. Laparoscopic two stage Fowler Stevens orchiopexy: vessels are divided with clips but dissection of the testis is postponed for 6 months to allow for optimal development of collaterals. 

If no testis is found during exploratory laparoscopy, one has to determine the presence of either blind ending vessels or a testicular nubbin to completely rule out a missing testis. The vas can be dissociated from the testis and thus is not always a good guide to find the gonad. [7]

If the internal ring is closed but vessels are going into it, a scrotal exploration usually will find a testicular nubbin. Look for a small structure with a brown spot.

If vessels are going into an open inguinal ring, one can usually push the testis into the abdomen but if not, an inguinal or scrotal exploration would be warranted.

A common diagnostic challenge is distinguishing a retractile testicle from a testicle that is not spontaneously descending into the scrotum. Retractile testes are more common than undescended testes and do not require surgical correction. In normal males, as the cremaster muscle contracts, the testicles retract into the upper scrotum and inguinal canal. This reflex is more active in infants. 

A retractile testicle high in the scrotum is difficult to distinguish from one positioned in the lower inguinal canal. Maneuvers used to assist identification include the cross-legged position, soaping the clinician's fingers, and examining the patient in a warm bath. 

The American Urological Association (AUA) Guidelines define a retractile testis as "...one that is initially extrascrotal on examination or moves easily out of the scrotal position, (often associated with a vigorous cremasteric reflex), but that can be manually replaced in a stable, dependent scrotal position and remain there without tension at least temporarily."

When properly diagnosed and treated, the prognosis is excellent. Testicular cancer risk and infertility remains somewhat increased compared to the general population.[8] However, a recent Danish study of over 6,000 men suggested testicular hypofunction, smaller testis volume (by 3.5 cc), 28% reduction in sperm concentration and reduced Leydig cell function in men with a history of cryptorchidism compared to normal men.[9]

[2]Orchiopexy is associated with two major testicular complications: atrophy and testicular ascent. For palpable testes, these occur less than 5% of the time. For laparoscopic orchiopexies, the rate is also around 5%. For Fowler-Stephens orchiopexies (dividing the vessels) in one or two stages, the testicular atrophy rate is around 20% to 30% (worse for the one stage procedure).

There may be a slight decrease in penis size in cryptorchid patients. 

It has been suggested that adjuvant LHRH treatment be offered to cryptorchid patients with a high risk for infertility due to their insufficient gonadotropin stimulation at the time of surgery. Sperm cryopreservation is another prophylactic option in case of resultant infertility in spite of the adjuvant LHRH.

Non-union, a rare anomaly involving the epididymis and testicle, can sometimes be mistaken for a testicular nubbin (atropic testis) when it's actually the vas and epididymis. The actual testicle in this condition is located proximally and can be identified via laparoscopy.[10]

An undescended testicle is the most prevalent male congenital defect affecting the male genitalia. Most (about 80%) will descend by the third month of life.  It is more frequently found in premature infants. Risks for male infertility and cancer are increased compared to the general population but still relatively small. Optimal timing of surgical orchidopexy (<18 months of age) is not always followed. Close collaboration and communication between nurse practitioners, physician assistants, pediatricians, and urologic surgeons will result in better outcomes and avoid unnecessary procedures while increasing the incidence of timely surgery when indicated.