Cryptorchidism, or undescended testicle refers to a testicle (testis) that has not moved into the scrotum (the bag of skin that hangs behind the penis) before a baby is born. It is estimated that 3% to 5% of newborn boys have undescended testicle(s). Premature newborn boys are much more likely to be born with an undescended testicle, compared to babies born at full term.

Cryptorchidism can also refer to both testicles undescended - and is much rarer (15% of cases). Whether it is just one or both testicles, cryptorchidism generally corrects itself within a few months. Sometimes surgery is needed to relocate the testicle into the scrotum.

What are the scrotum and testicles? The scrotum is a small pouch (sac) of skin that hangs behind (under) the penis. The scrotum holds the testicles in place. The scrotum also holds the edpididymes (a structure within the scrotum attached to the backside of the testis) and lower portions of spermatic cords. (Testis = testicle. Testes = Testicles).

A pair of testicles (testes) is located inside the scrotum. The testicles are oval-shaped sex organs that form part of the male reproductive system. The testicles produce sperm and testosterone. Testosterone is a hormone which plays a key role in male sexual development, such as the development of the reproductive organs, body and facial hair, low voice, and wide shoulders.

The medical word cryptorchidism comes from the Greek word kryptos which means "hidden", and the Greek word orchis which means "testis, testicle".

According to Medilexicon's medical dictionary: Cryptorchidism means "Failure of one or both testes to descend." During pregnancy a baby's testicles form in his abdomen, before gradually descending into the scrotum, usually around the 8th month. Experts are not sure why sometimes one of them, or both, do not descend. What are the signs and symptoms of cryptorchidism (undescended testicle)? A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.

Doctors generally refer to palpable undescended testicles or unpalpable undescended testicles. Palpable undescended testicles - the testicle(s) can be felt during a physical examination. Accounts for about 80% of cases. The testicle(s) is usually located at the end of the inguinal canal, where it is lodged. The inguinal canal is a channel in the anterior abdominal wall which conveys the spermatic cord towards the penis and scrotum in males. Unpalpable undescended testicles - the testicle(s) can't be felt during a physical examination. There are three main types:

Abdominal or intra-abdominal - the testicle is inside the abdomen, generally near the upper opening of the inguinal canal. These account for about 40% of cases of unpalpable testicles. Inguinal - the testicle has moved into the inguinal canal (which it should), but has not moved down enough to be detected by touch (unpalpable). These account for about 40% of unpalpable testicles. Atrophic or absent - an atrophic testicle is very small, while an absent one was never formed (it is missing). These account for about 20% of cases of unpalpable testicles. What are the risk factors for cryptorchidism (undescended testicle)? A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2. The following risk factors are linked to cryptorchidism: Premature birth - the earlier the baby boy is born, the higher the risk. Low birth weight - boys who weigh less than 5.5lb (2.5 kilograms) at birth are two to three times more likely to be born with undescended testicles, compared to boys of normal birth weight. Alcohol consumption during pregnancy by the mother Down syndrome and other conditions of the fetus that can hamper growth Exposure to pesticides by either or both parents Family history of problems of genital development, including cryptorchidism - a baby boy whose older brother was born with an undescended testicle(s) is twice as likely to be born with the same condition, compared to babies whose older brother was not born with the condition. Tobacco smoking by the mother during pregnancy Type 1 diabetes, type 2 diabetes, or gestational diabetes in the mother - a mother with diabetes is twice as likely to give birth to a boy with an undescended testicle(s), compared to mothers without diabetes. What are the causes of cryptorchidism (undescended testicle)? Early on in the pregnancy all embryos have identical genitals, regardless of sex. The baby receives a pair of sex chromosomes from its mother and father. Sex chromosomes are a pair of DNA molecules - XX if the human is female, XY if the human is male.

At a certain stage in the unborn male baby's development the testicles start to form; once they are formed they stay inside the baby's abdomen until about the 7th month of pregnancy. Experts believe that at this point some hormones trigger the descent of the testes - they make their way down the abdomen, through the inguinal canal, and into the scrotum. In about 97% of cases the testicles are in the scrotum before birth.

During the 9th week of pregnancy, the male baby will start producing testosterone. Testosterone is a hormone which triggers the development of male genitals. The production of testosterone is triggered by the male sexual chromosomes XY. Experts believe that the problems linked to absent or atrophic testicles arise at this stage.

Abnormal genital development may also be caused by androgen insensitivity syndrome (androgen resistance syndrome). This is a genetic disorder in which XY fetuses are unresponsive (insensitive) to male hormones (androgens, such as testosterone). The baby is born looking like a normal girl externally. They have a short-blind pouch vagina, but no uterus, ovaries or fallopian tubes. Testes are present in the abdomen or the inguinal canal.

Experts say that in the majority of cryptorchidism cases, a combination of genetics, maternal health and some environmental factors disrupt the hormones, physical changes and nerve activity that bring about the development of the testicles. However, nobody knows what the exact cause is.

Testicular dysgenesis syndrome (TDS) - this describes four conditions which have become more prevalent in Western countries over the last thirty years; they include: Decreased spermatogenesis (low sperm count) Testicular cancers Hyposdadias - the tube in the penis through which urine passes (urethra) is not in the right place Cryptorchidism (undescended testicle) Some scientists suggest that these four conditions are linked (not separate conditions); i.e. they form part of one syndrome (testicular dysgenesis syndrome).

Nobody is sure whether testicular dysgenesis syndrome exists. If it does, scientists believe chemical exposure during pregnancy may undermine normal hormonal balance, which interferes with the proper development of male genitals.

Chemicals that disrupt hormonal balance are called endocrine disruptors, and include some pesticides, PCBs (polychlorinated biphenyls), and dibutyl phthalate. Diagnosing cryptorchidism (undescended testicle) During a physical examination of the newborn male baby a doctor can easily determine whether the testicles have descended into the scrotum. The baby is usually placed in a warm bath to help him relax, while at the same time expanding the skin around the scrotum, making it easier to carry out the examination.

If the testicle is not in the scrotum and cannot be felt (unpalpable) - which occurs in about 20% of cryptorchidism cases - the baby will most likely be referred to a pediatric urologist for further tests. The following diagnostic tests may be ordered: Ultrasound scan - an imaging device that utilizes sound waves to create images of the inside of the body. This type of scan is particularly useful in locating the testicle if it is in the groin. MRI (magnetic resonance imaging) scan - uses a magnetic field and radio waves to create detailed images of the body. A contrast agent (dye) will most likely to used - it is injected into the bloodstream. This type of scan helps the doctor locate the testicle if it is in the groin or abdomen. Laparoscopy - a laparoscope; a tube with a tiny video camera attached to the end is inserted through a small incision in the patient's abdomen. The undescended testicle may be corrected surgically during this procedure. Open surgery - in rare complicated cases the surgeon may have to explore directly in the abdomen through a larger incision. If both testes are undescended the doctor may wish to test the sex of the baby. Sometimes a female baby may have external male genitals (ambiguous genitalia). The following tests may be ordered: Blood and urine tests - to measure hormone levels Sex-related gene test Ultrasound scan to determine whether the baby has any ovaries What are the treatment options for cryptorchidism (undescended testicle)? Orchidopexy (orchiopexy) - the surgical treatment of an undescended testicle by freeing it and implanting it into the scrotum. Orchidopexy is commonly recommended for cases of undescended testicle(s).

The procedure is usually carried out when the boy is aged between 6 and 18 months. There is a higher risk of eventually developing testicular cancer, or having fertility problems later in life if the operation is delayed for more than two years.

Keyhole (laparoscopic) surgery is commonly used these days for orchidopexies. The surgeon makes a small incision in the boy's abdomen and then passes small surgical instruments through it. The testicle is moved down the inguinal canal and placed in the scrotum using a second incision. Typically, the inguinal canal is sealed to stop the testicle from going back up. In most cases, the patient will be able to go back home on the same day as the surgery. For a period of about 24 hours the child may feel sick - this is normal.

According to the National Health Service (NHS), UK, the success rates for treating palpable testicles located near the scrotum are between 80% and 90%, and between 75% and 90% for unpalpable testicles. If the operation is unsuccessful, the child may have to undergo another operation.

Hormone therapy - sometimes synthetic hormones may be used to get the testicle to go down into the scrotum. This type of therapy is only used if the testicle(s) is close to the scrotum; it is not effective if the unpalpable testicle(s) is in the inguinal canal or abdomen. If the child's testicles are not descended and blood tests have shown there is an underlying hormonal problem, hormone therapy may be recommended. What are the possible complications of cryptorchidism (undescended testicle)? The testes normally exist in the scrotum because the temperature in there is slightly lower than body temperature. The testicles need a slightly lower-than-body temperature to function properly. The testicles undergo changes that affect how well they function later in life - these changes occur until a boy is 3 to 4 years old.

If the testicle has not descended it will not be in its ideal temperature - its environment will be too hot. The following complications are possible: Testicular cancer - men who were born with an undescended testicle(s) have a higher risk of developing testicular cancer, compared to other men. Fertility problems - men who were born with an undescended testicle(s) have a high risk of having:

Low sperm counts Poor sperm quality Poor fertility The following complications are also possible: Testicular torsion - the spermatic cord is twisted. The spermatic cord contains nerves, blood vessels and tubes that carry semen to from the testicle to the penis. Left untreated the individual can lose the affected testicle. People born with an undescended testicle(s) have a higher risk of developing testicular torsion. Damage to the testicle - if the undescended testicle is in the groin, pressure from the pubic bone could damage it. Inguinal hernia - a portion of the intestines can push into the groin. Vas deferens damage - this may occur during an orchidopexy (surgery). The vas deferens is a tube that connects the testicle to the urethra (tube through which sperm passes when a male ejaculates). If this occurs further surgery will be required to repair the damage.