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| {{Cryptorchidism}} | | {{Cryptorchidism}} |
| | '''For patient information, click [[Cryptorchidism (patient information)|here]]''' |
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| {{CMG}} | | {{CMG}} {{AE}} {{SME}} |
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| {{SK}} Cryptorchism; maldescended testis; ectopic testis; undescended testicle | | {{SK}} Cryptorchism; maldescended testis; ectopic testis; undescended testicle |
| | ==[[Cryptorchidism overview|Overview]]== |
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| ==Overview== | | ==[[Cryptorchidism historical perspective|Historical Perspective]]== |
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| Cryptorchidism is the absence of one or both [[testes]] from the [[scrotum]]. This usually represents failure of the testis to move, or descend, during fetal development from an [[abdomen|abdominal]] position, through the [[inguinal canal]], into the ipsilateral scrotum. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis, making cryptorchidism the most common [[birth defect]] of male [[genitalia]]. However, most testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1% overall.
| | ==[[Cryptorchidism classification|Classification]]== |
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| A testis absent from the normal scrotal position can be:
| | ==[[Cryptorchidism pathophysiology|Pathophysiology]]== |
| #found anywhere along the "path of descent" from high in the posterior (retroperitoneal) abdomen, just below the [[kidney]], to the inguinal ring;
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| #found in the inguinal canal;
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| #''[[ectopic]]'', that is, found to have "wandered" from that path, usually outside the inguinal canal and sometimes even under the skin of the thigh, the [[perineum]], the opposite scrotum, and femoral canal;
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| #found to be undeveloped (''hypoplastic'') or severely abnormal (''dysgenetic'');
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| #found to have vanished (also see [[Anorchia]]).
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| About two thirds of cases without other abnormalities are unilateral; 1/3 involve both testes. In 90% of cases an undescended testis can be ''palpated'' (felt) in the inguinal canal; in a minority the testis or testes are in the abdomen or nonexistent (truly "hidden").
| | ==[[Cryptorchidism causes|Causes]]== |
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| Undescended testes are associated with reduced [[fertility]], increased risk of testicular germ cell tumors and psychological problems when the boy is grown. Undescended testes are also more susceptible to [[testicular torsion]] and infarction and inguinal hernias. To reduce these risks, undescended testes are usually brought into the scrotum in infancy by a surgical procedure called an [[orchiopexy]].
| | ==[[Cryptorchidism differential diagnosis|Differentiating Cryptorchidism from other Diseases]]== |
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| Although cryptorchidism nearly always refers to ''[[congenital]]'' absence or maldescent, a testis observed in the scrotum in early infancy can occasionally "reascend" (move back up) into the inguinal canal. A testis which can readily move or be moved between the scrotum and canal is referred to as ''retractile''.
| | ==[[Cryptorchidism epidemiology and demographics|Epidemiology and Demographics]]== |
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| == Terminology == | | ==[[Cryptorchidism risk factors|Risk Factors]]== |
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| '''''Cryptorchidism''''' is derived from the Greek words "crypto" (meaning "hidden") and "orchid" (meaning "testicle"). During the last century, cryptorchidism was sometimes restricted to the subset of undescended testes that were not palpable above the scrotum or in the [[inguinal]] canal — those that were truly hidden in the [[abdomen]] or completely absent. In recent decades the distinction is no longer made in most contexts, and the two terms are used interchangeably. ''Cryptorchism'' is an older variant of the same term.
| | ==[[Cryptorchidism natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| == Normal fetal testicular development and descent == | | ==Diagnosis== |
| | [[Cryptorchidism history and symptoms|History and Symptoms]] | [[Cryptorchidism physical examination|Physical Examination]] | [[Cryptorchidism laboratory findings|Laboratory Findings]] | [[Cryptorchidism CT|CT]] | [[Cryptorchidism MRI|MRI]] | [[Cryptorchidism abdominal ultrasound|Abdominal Ultrasound]] | [[Cryptorchidism other imaging findings|Other Imaging Findings]] |
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| The testes begin as an immigration of primordial [[germ cell]]s into testicular cords along the [[genital ridge]] in the abdomen of the early embryo. The interaction of several male [[gene]]s organizes this developing [[gonad]] into a [[testis]] rather than an [[ovary]] by the second month of [[gestation]]. During the 3rd to 5th months, the cells in the testes differentiate into [[testosterone]]-producing [[Leydig cell]]s, and [[anti-müllerian hormone]]-producing [[Sertoli cell]]s. The germ cells in this environment become fetal [[spermatogonia]]. Male external [[genitalia]] during the 3rd and 4th months of gestation and the [[fetus]] continues to grow, develop, and differentiate.
| | ==Treatment== |
| | [[Cryptorchidism medical therapy|Medical Therapy]] | [[Cryptorchidism surgery |Surgery]] | [[Cryptorchidism cost-effectiveness of therapy | Cost-Effectiveness of Therapy]] | [[Cryptorchidism future or investigational therapies | Future or Investigational Therapies]] |
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| The testes remain high in the abdomen until the 7th month of gestation, when they move from the abdomen through the inguinal canals into the two sides of the [[scrotum]]. It has been proposed that movement occurs in two phases, under control of somewhat different factors. The first phase, movement across the abdomen to the entrance of the inguinal canal appears controlled (or at least greatly influenced) by anti-müllerian hormone (AMH). The second phase, in which the testes move through the inguinal canal into the scrotum, is dependent on [[androgen]]s (most importantly testosterone). In rodents, androgens induce the [[genitofemoral nerve]] to release [[calcitonin gene-related peptide]] (CGRP), which produces rhythmic contractions of the [[gubernaculum]], a [[ligament]] which connects the testis to the scrotum, but a similar mechanism has not been demonstrated in humans. Maldevelopment of the gubernaculum, or deficiency or insensitivity to either AMH or androgen therefore can prevent the testes from descending into the scrotum. Some evidence suggests there may even be an additional [[paracrine]] hormone, referred to as ''descendin'', secreted by the testes.
| | == Case Studies == |
| | | [[Cryptorchidism case study one|Case #1]] |
| In many infants with inguinal testes, further descent of the testes into the scrotum occurs in the first 6 months of life. This is attributed to the postnatal surge of [[gonadotropin]]s and testosterone that normally occurs between the first and fourth months of life.
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| [[Spermatogenesis]] continues after birth. In the 3rd to 5th months of life, some of the ''fetal spermatogonia'' residing along the [[basement membrane]] become ''type A spermatogonia''. More gradually, other fetal spermatogonia become ''type B spermatogonia'' and ''primary spermatocytes'' by the 5th year after birth. Spermatogenesis arrests at this stage until [[puberty]].
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| Most normal-appearing undescended testis are also normal by microscopic examination, but reduced spermatogonia can be found. The tissue in undescended testes becomes more markedly abnormal ("degenerates") in microscopic appearance between 2 and 4 years after birth. There is some evidence that early [[orchiopexy]] reduces this degeneration.
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| == Causes == | |
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| In most full-term infant boys with cryptorchidism but no other [[genital]] abnormalities, a cause cannot be found, making this a common, sporadic, unexplained ([[idiopathic]]) birth defect.
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| Although severely [[prematurity|premature]] infants can be born before descent of testes, there is a strong association of cryptorchidism with low birthweight due to either prematurity or [[intrauterine growth retardation]]. In these infants there is usually no evidence of [[hormonal]] malfunction. Associated [[inguinal hernia]]s are common.
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| Hormonal abnormalities (deficiency or insensitivity to androgens or anti-müllerian hormone) can be demonstrated in a high proportion of those with evidence of under[[virilization]] or [[ambiguous genitalia|ambiguity]] such as [[hypospadias]] or [[micropenis]].
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| A contributing role of environmental [[chemical]]s — [[endocrine disruptor]]s — that interfere with normal fetal hormone balance has been proposed as well, similar to the effects of [[diethylstilbestrol]] exposure. It is rarely possible to implicate a specific chemical exposure for an individual child.
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| Occasional instances of other genetic defects involving development or function of the [[gubernaculum]] have been reported. [[Homeobox]] [[gene]] [[mutation]]s can cause cryptorchidism in animals but remain a largely theoretical possibility in humans.
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| Rare [[iatrogenic]] cases have also been reported in which hernia repair or other surgery in the inguinal area resulted in trapping of a [[testis]] above the [[scrotum]].
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| A 2006 study showed that regular alcohol consumption during pregnancy (5 or more drinks per week) is associated with a 3x increase in cryptorchidism, when compared to non-drinking mothers. Other previously known risk factors include exposure to [[pesticides]], low birth weight (including premature birth), gestational diabetes and being a twin [http://www.sciencenews.org/articles/20070106/food.asp].
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| == Inheritance and recurrence risk ==
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| A small percentage of cases of isolated cryptorchidism are [[familial]]. It has been reported that about 4% of fathers and 6-10% of brothers of affected boys have also had cryptorchidism. Few specific genes associated with isolated cryptorchidism have been identified.
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| In contrast, many of the genes causing some of the [[intersex]] conditions associated with androgen or AMH deficiency or insensitivity have been identified, and [[genetic counseling]] to explain recurrence risk to families is appropriate.
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| A new study shows that pregnant women who drink caffeine (at least 3drinks per day*) will increase the risk of cryptorchidism. http://www.medscape.com/viewarticle/570489?src=mpnews
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| == Associations ==
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| Cryptorchidism occurs at a much higher rate in a large number of [[congenital disorder|congenital malformation syndromes]]. Among the more common are [[Prader-Willi syndrome]], [[Noonan syndrome]], and [[cloacal exstrophy]]. | |
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| == Diagnosis ==
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| The most common diagnostic dilemma in otherwise normal boys is distinguishing a [[retractile testis]] from a testis that will not/cannot descend spontaneously into the scrotum. Retractile testes are more common than truly undescended testes and do not need to be operated on. In normal males, as the [[cremaster muscle]] relaxes or contracts, the testis moves lower or higher ("retracts") in the scrotum. This [[cremasteric reflex]] is much more active in infant boys than older men. A retractile testis high in the scrotum can be difficult to distinguish from a position in the lower inguinal canal. Though there are various maneuvers used to do so, such as using a crosslegged position, soaping the examiner's fingers, or examining in a warm bath, the benefit of surgery in these cases can be a matter of clinical judgement.
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| In the minority of cases with bilaterally non-palpable testes, further testing to locate the testes, assess their function, and exclude additional problems is often useful. Pelvic [[ultrasound]] or [[magnetic resonance imaging]] can often, but not invariably, locate the testes while confirming absence of a uterus. A [[karyotype]] can confirm or exclude forms of dysgenetic primary hypogonadism, such as [[Klinefelter syndrome]] or [[mixed gonadal dysgenesis]].
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| Hormone levels (especially gonadotropins and AMH) can help confirm that there are hormonally functional testes worth attempting to rescue, as can stimulation with a few injections of [[human chorionic gonadotropin]] to elicit a rise of the testosterone level. Occasionally these tests reveal an unsuspected and more complicated [[intersex]] condition.
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| In the even smaller minority of cryptorchid infants who have other obvious birth defects of the genitalia, further testing is crucial and has a high likelihood of detecting an [[intersex]] condition or other anatomic anomalies. Ambiguity can indicate either impaired androgen synthesis or [[androgen insensitivity syndrome|reduced sensitivity]]. The presence of a [[uterus]] by pelvic [[ultrasound]] suggests either [[persistent müllerian duct syndrome]] (AMH deficiency or insensitivity) or a severely virilized genetic female with [[congenital adrenal hyperplasia]]. An unambiguous [[micropenis]], especially accompanied by [[hypoglycemia]] or [[jaundice]], suggests congenital [[hypopituitarism]].
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| == Treatment ==
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| The primary management of cryptorchidism is surgery, called [[orchiopexy]]. It is usually performed in infancy, if inguinal testes have not descended after 4-6 months, often by a [[pediatric urologist]] or pediatric surgeon, but in many communities still by a general [[urologist]] or surgeon.
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| When the undescended testis is in the inguinal canal, hormonal therapy is sometimes attempted and occasionally successful. The most commonly used hormone therapy is human chorionic gonadotropin. A series of hCG injections (10 injections over 5 weeks is common) is given and the status of the testis/testes is reassessed at the end. Although many trials have been published, the reported success rates range widely, from roughly 5 to 50%, probably reflecting the varying criteria for distinguishing retractile testes from low inguinal testes. Hormone treatment does have the occasional incidental benefits of allowing confirmation of Leydig cell responsiveness (proven by a rise of the testosterone by the end of the injections) or inducing additional growth of a small penis (via the testosterone rise). Some surgeons have reported facilitation of surgery, perhaps by enhancing the size, vascularity, or healing of the tissue. A newer hormonal intervention used in Europe is use of [[GnRH analog]]s such as [[nafarelin]] or [[buserelin]]; the success rates and putative mechanism of action are similar to hCG, but some surgeons have combined the two treatments and reported higher descent rates. Limited evidence suggests that germ cell count is slightly better after hormone treatment; whether this translates into better sperm counts and fertility rates at maturity has not been established. The cost of either type of hormone treatment is less than that of surgery and the chance of complications at appropriate doses is minimal. Nevertheless, despite the potential advantages of a trial of hormonal therapy, many surgeons do not consider the success rates high enough to be worth the trouble since the surgery itself is usually simple and uncomplicated.
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| In cases where the testes are identified preoperatively in the inguinal canal, orchiopexy is often performed as an outpatient and has a very low complication rate. An incision is made over the inguinal canal. The testis with accompanying cord structure and blood supply is exposed, partially separated from the surrounding tissues ("mobilized"), and brought into the scrotum. It is sutured to the scrotal tissue or enclosed in a "subdartos pouch." The associated passage back into the inguinal canal, an [[inguinal hernia]], is closed to prevent re-ascent.
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| Surgery becomes more complicated if the blood supply is not ample and elastic enough to be stretched into the scrotum. In these cases, the supply may be divided, some vessels sacrificed with expectation of adequate [[collateral circulation]]. In the worst case, the testis must be "auto-transplanted" into the scrotum, with all connecting blood vessels cut and reconnected ("[[anastomosis|anastomosed]]").
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| When the testis is in the abdomen, the first stage of surgery is exploration to locate it, assess its viability, and determine the safest way to maintain or establish the blood supply. Multi-stage surgeries, or auto-transplantation and anastomosis, are more often necessary in these situations. Just as often, intra-abdominal exploration discovers that the testis is non-existent ([[vanishing testes syndrome|"vanished"]]), or dysplastic and not salvageable.
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| The principal major complication of all types of orchiopexy is loss of the blood supply to the testis, resulting in loss of the testis due to [[ischemia|ischemic]] [[atrophy]] or [[fibrosis]].
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| There have been cases where the condition has resolved itself during contact sports, following blunt force to the abdomen. However, this technique is not recommended because the impact sufficient to 'pop' the testicle into place may cause trauma to the abdomen.
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| ==Infertility==
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| ===Prevalence===
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| Many men who were born with undescended testes have reduced [[fertility]], even after [[orchiopexy]] in infancy. The reduction with unilateral cryptorchidism is subtle, with a reported infertility rate of about 10%, compared with about 6% reported by the same study for the general population of adult men.
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| The fertility reduction after orchiopexy for bilateral cryptorchidism is more marked, about 38%, or 6 times that of the general population. The basis for the universal recommendation for early surgery is research showing degeneration of spermatogenic tissue and reduced spermatogonia counts after the second year of life in undescended testes. The degree to which this is prevented or improved by early orchiopexy is still uncertain.
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| ===Pathophysiology===
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| At least one contributing mechanism for reduced spermatogenesis in cryptorchid testes is temperature. The temperature of testes in the scrotum is at least a couple of degrees cooler than in the abdomen. Animal experiments in the middle of the 20th century suggested that raising the temperature could damage fertility. Some circumstantial evidence suggests tight underwear and other practices that raise testicular temperature for prolonged periods can be associated with lower [[sperm count]]s. Nevertheless, research in recent decades suggests that the issue of fertility is more complex than a simple matter of temperature. It seems likely that subtle or transient hormone deficiencies or other factors that lead to lack of descent also impair the development of spermatogenic tissue.
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| The inhibition of spermatogenesis by ordinary intra-abdominal temperature is so potent that continual suspension of normal testes tightly against the inguinal ring at the top of the scrotum by means of special "suspensory briefs" has been researched as a method of [[male contraception]], and was referred to as "artificial cryptorchidism" by one report.
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| An additional factor contributing to infertility is the high rate of anomalies of the [[epididymis]] in boys with cryptorchidism (over 90% in some studies). Even after orchiopexy, these may also affect sperm maturation and motility at an older age.
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| == Later cancer risk ==
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| One of the strongest arguments for early orchiopexy is prevention of [[testicular cancer]]. About 1 in 500 men born with one or both testes undescended develops testicular cancer, roughly a 4- to 40-fold increased risk. The peak incidence occurs in the 3rd and 4th decades of life. The risk is higher for intra-abdominal testes and somewhat lower for inguinal testes, but even the ''normally descended'' testis of a man whose other testis was undescended has about a 20% higher cancer risk than those of other men.
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| The most common type of testicular cancer occurring in undescended testes is [[seminoma]]. It is usually treatable if caught early, so urologists often recommend that boys who had orchiopexy as infants be taught [[testicular self-examination]], to recognize testicular masses and seek early medical care for them. Cancer developing in an intra-abdominal testis would be unlikely to be recognized before considerable growth and spread, and one of the advantages of orchiopexy is that a mass developing in a scrotal testis is simply far easier to recognize than an intra-abdominal mass.
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| Although orchiopexy makes cancer more easily recognizable at an early stage, whether early orchiopexy actually ''reduces'' the chance of developing cancer remains a subject of controversy. As with infertility, the causes of cancer associated with cryptorchidism are not known. Most evidence suggests the cancer risk is due to an inherent abnormality of the undescended testis rather than to the ability of an abdominal location to cause cancer in an otherwise normal testis.
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| The risk of malignancy in the undescended testis is 4 to 10 times higher than that in the general population and is approximately 1 in 80 with a unilateral undescended testis and 1 in 40 to 1 in 50 for bilateral undescended testes. The peak age for this tumor is 15–45 yr. The most common tumor developing in an undescended testis is a seminoma (65%); in contrast, after orchiopexy, seminomas represent only 30% of testis tumors.
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| == References ==
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| * Docimo SG. The results of surgical therapy for cryptorchidism: a literature review and analysis. J Urol 1995 Sep; 154(3): 1148-52. PMID 7637073
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| * Kolon TF, Patel RP, Huff DS. Cryptorchidism: diagnosis, treatment, and long-term prognosis. Urol Clin North Am. 2004 Aug;31(3):469-80, viii-ix. PMID 15313056
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| * Møller H, Cortes D, Engholm G, Thorup J. Risk of testicular cancer with cryptorchidism and with testicular biopsy: cohort study. BMJ. 1998 Sep 12; 317(7160): 729-730. [http://www.pubmedcentral.gov/articlerender.fcgi?tool=pmcentrez&artid=28664]
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| ==External links==
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| {{Congenital malformations of genital organs and urinary system}} | | {{Congenital malformations of genital organs and urinary system}} |
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| [[Category:Andrology]]
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| [[Category:Primary care]]
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| [[Category:Diseases]]
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| [[da:Kryptorchisme]] | | [[da:Kryptorchisme]] |
| [[de:Lageanomalie des Hodens]] | | [[de:Lageanomalie des Hodens]] |
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| [[fi:Piilokiveksisyys]] | | [[fi:Piilokiveksisyys]] |
| [[sv:Kryptorkism]] | | [[sv:Kryptorkism]] |
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