Testicles, or testes, make male hormones and sperm. They are two egg-shaped organs inside the scrotum, the loose sac of skin behind the penis. It's easy to injure your testicles because they are not protected by bones or muscles. Men and boys should wear athletic supporters when they play sports.

You should examine your testicles monthly and seek medical attention for lumps, redness, pain or other changes. Testicles can get inflamed or infected. They can also develop cancer. Testicular cancer is rare and highly treatable. It usually happens between the ages of 15 and 40.

The male gonads, testes or testicles, begin their development high in the abdominal cavity, near the kidneys. During the last two months before birth, or shortly after birth, they descend through the inguinal canal into the scrotum, a pouch that extends below the abdomen, posterior to the penis. Although this location of the testes, outside the abdominal cavity, may seem to make them vulnerable to injury, it provides a temperature about 3° C below normal body temperature. This lower temperature is necessary for the production of viable sperm.

The scrotum consists of skin and subcutaneous tissue. A vertical septum, or partition, of subcutaneous tissue in the center divides it into two parts, each containing one testis. Smooth muscle fibers, called the dartos muscle, in the subcutaneous tissue contract to give the scrotum its wrinkled appearance. When these fibers are relaxed, the scrotum is smooth. Another muscle, the cremaster muscle, consists of skeletal muscle fibers and controls the position of the scrotum and testes. When it is cold or a man is sexually aroused, this muscle contracts to pull the testes closer to the body for warmth.

Structure

Each testis is an oval structure about 5 cm long and 3 cm in diameter. A tough, white fibrous connective tissue capsule, the tunica albuginea, surrounds each testis and extends inward to form septa that partition the organ into lobules. There are about 250 lobules in each testis. Each lobule contains 1 to 4 highly coiled seminiferous tubules that converge to form a single straight tubule, which leads into the rete testis. Short efferent ducts exit the testes. Interstitial cells (cells of Leydig), which produce male sex hormones, are located between the seminiferous tubules within a lobule.

Spermatogenesis

Sperm are produced by spermatogenesis within the seminiferous tubules. A transverse section of a seminiferous tubule shows that it is packed with cells in various stages of development. Interspersed with these cells, there are large cells that extend from the periphery of the tubule to the lumen. These large cells are the supporting, or sustentacular cells (Sertoli's cells), which support and nourish the other cells.

Early in embryonic development, primordial germ cells enter the testes and differentiate into spermatogonia, immature cells that remain dormant until puberty. Spermatogonia are diploid cells, each with 46 chromosomes (23 pairs) located around the periphery of the seminiferous tubules. At puberty, hormones stimulate these cells to begin dividing by mitosis. Some of the daughter cells produced by mitosis remain at the periphery as spermatogonia. Others are pushed toward the lumen, undergo some changes, and become primary spermatocytes. Because they are produced by mitosis, primary spermatocytes, like spermatogonia, are diploid and have 46 chromosomes.

Each primary spermatocytes goes through the first meiotic division, meiosis I, to produce two secondary spermatocytes, each with 23 chromosomes (haploid). Just prior to this division, the genetic material is replicated so that each chromosome consists of two strands, called chromatids, that are joined by a centromere. During meiosis I, one chromosome, consisting of two chromatids, goes to each secondary spermatocyte. In the second meiotic division, meiosis II, each secondary spermatocyte divides to produce two spermatids. There is no replication of genetic material in this division, but the centromere divides so that a single-stranded chromatid goes to each cell. As a result of the two meiotic divisions, each primary spermatocyte produces four spermatids. During spermatogenesis there are two cellular divisions, but only one replication of DNA so that each spermatid has 23 chromosomes (haploid), one from each pair in the original primary spermatocyte. Each successive stage in spermatogenesis is pushed toward the center of the tubule so that the more immature cells are at the periphery and the more differentiated cells are nearer the center.

Spermatogenesis (and oogenesis in the female) differs from mitosis because the resulting cells have only half the number of chromosomes as the original cell. When the sperm cell nucleus unites with an egg cell nucleus, the full number of chromosomes is restored. If sperm and egg cells were produced by mitosis, then each successive generation would have twice the number of chromosomes as the preceding one.

The final step in the development of sperm is called spermiogenesis. In this process, the spermatids formed from spermatogenesis become mature spermatozoa, or sperm. The mature sperm cell has a head, midpiece, and tail. The head, also called the nuclear region, contains the 23 chromosomes surrounded by a nuclear membrane. The tip of the head is covered by an acrosome, which contains enzymes that help the sperm penetrate the female gamete. The midpiece, metabolic region, contains mitochondria that provide adenosine triphosphate (ATP). The tail or locomotor region, uses a typical flagellum for locomotion. The sperm are released into the lumen of the seminiferous tubule and leave the testes. They then enter the epididymis where they undergo their final maturation and become capable of fertilizing a female gamete.

Sperm production begins at puberty and continues throughout the life of a male. The entire process, beginning with a primary spermatocyte, takes about 74 days. After ejaculation, the sperm can live for about 48 hours in the female reproductive tract.

The testes (singular = testis) are the male gonads—that is, the male reproductive organs. They produce both sperm and androgens, such as testosterone, and are active throughout the reproductive lifespan of the male.

Paired ovals, the testes are each approximately 4 to 5 cm in length and are housed within the scrotum (see image). They are surrounded by two distinct layers of protective connective tissue (image). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer. Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a male fetus, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis.” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth.

The tightly coiled seminiferous tubules form the bulk of each testis. They are composed of developing sperm cells surrounding a lumen, the hollow center of the tubule, where formed sperm are released into the duct system of the testis. Specifically, from the lumens of the seminiferous tubules, sperm move into the straight tubules (or tubuli recti), and from there into a fine meshwork of tubules called the rete testes. Sperm leave the rete testes, and the testis itself, through the 15 to 20 efferent ductules that cross the tunica albuginea.

Inside the seminiferous tubules are six different cell types. These include supporting cells called sustentacular cells, as well as five types of developing sperm cells called germ cells. Germ cell development progresses from the basement membrane—at the perimeter of the tubule—toward the lumen. Let’s look more closely at these cell types.

Sertoli Cells

Surrounding all stages of the developing sperm cells are elongate, branching Sertoli cells. Sertoli cells are a type of supporting cell called a sustentacular cell, or sustentocyte, that are typically found in epithelial tissue. Sertoli cells secrete signaling molecules that promote sperm production and can control whether germ cells live or die. They extend physically around the germ cells from the peripheral basement membrane of the seminiferous tubules to the lumen. Tight junctions between these sustentacular cells create the blood–testis barrier, which keeps bloodborne substances from reaching the germ cells and, at the same time, keeps surface antigens on developing germ cells from escaping into the bloodstream and prompting an autoimmune response.

Germ Cells

The least mature cells, the spermatogonia (singular = spermatogonium), line the basement membrane inside the tubule. Spermatogonia are the stem cells of the testis, which means that they are still able to differentiate into a variety of different cell types throughout adulthood. Spermatogonia divide to produce primary and secondary spermatocytes, then spermatids, which finally produce formed sperm. The process that begins with spermatogonia and concludes with the production of sperm is called spermatogenesis.

Spermatogenesis

As just noted, spermatogenesis occurs in the seminiferous tubules that form the bulk of each testis (see image). The process begins at puberty, after which time sperm are produced constantly throughout a man’s life. One production cycle, from spermatogonia through formed sperm, takes approximately 64 days. A new cycle starts approximately every 16 days, although this timing is not synchronous across the seminiferous tubules. Sperm counts—the total number of sperm a man produces—slowly decline after age 35, and some studies suggest that smoking can lower sperm counts irrespective of age.

The process of spermatogenesis begins with mitosis of the diploid spermatogonia (image). Because these cells are diploid (2n), they each have a complete copy of the father’s genetic material, or 46 chromosomes. However, mature gametes are haploid (1n), containing 23 chromosomes—meaning that daughter cells of spermatogonia must undergo a second cellular division through the process of meiosis.

Two identical diploid cells result from spermatogonia mitosis. One of these cells remains a spermatogonium, and the other becomes a primary spermatocyte, the next stage in the process of spermatogenesis. As in mitosis, DNA is replicated in a primary spermatocyte, before it undergoes a cell division called meiosis I. During meiosis I each of the 23 pairs of chromosomes separates. This results in two cells, called secondary spermatocytes, each with only half the number of chromosomes. Now a second round of cell division (meiosis II) occurs in both of the secondary spermatocytes. During meiosis II each of the 23 replicated chromosomes divides, similar to what happens during mitosis. Thus, meiosis results in separating the chromosome pairs. This second meiotic division results in a total of four cells with only half of the number of chromosomes. Each of these new cells is a spermatid. Although haploid, early spermatids look very similar to cells in the earlier stages of spermatogenesis, with a round shape, central nucleus, and large amount of cytoplasm. A process called spermiogenesis transforms these early spermatids, reducing the cytoplasm, and beginning the formation of the parts of a true sperm. The fifth stage of germ cell formation—spermatozoa, or formed sperm—is the end result of this process, which occurs in the portion of the tubule nearest the lumen. Eventually, the sperm are released into the lumen and are moved along a series of ducts in the testis toward a structure called the epididymis for the next step of sperm maturation.

Scrotum is a sac containing testes; exterior to the body.

The testes are located in a skin-covered, highly pigmented, muscular sack called the scrotum that extends from the body behind the penis (see image). This location is important in sperm production, which occurs within the testes, and proceeds more efficiently when the testes are kept 2 to 4°C below core body temperature.

The dartos muscle makes up the subcutaneous muscle layer of the scrotum (image). It continues internally to make up the scrotal septum, a wall that divides the scrotum into two compartments, each housing one testis. Descending from the internal oblique muscle of the abdominal wall are the two cremaster muscles, which cover each testis like a muscular net. By contracting simultaneously, the dartos and cremaster muscles can elevate the testes in cold weather (or water), moving the testes closer to the body and decreasing the surface area of the scrotum to retain heat. Alternatively, as the environmental temperature increases, the scrotum relaxes, moving the testes farther from the body core and increasing scrotal surface area, which promotes heat loss. Externally, the scrotum has a raised medial thickening on the surface called the raphae.

Problems with the penis can cause pain and affect a man's sexual function and fertility. Penis disorders include

• Erectile dysfunction - inability to get or keep an erection
• Priapism - a painful erection that does not go away
• Peyronie's disease - bending of the penis during an erection due to a hard lump called a plaque
• Balanitis - inflammation of the skin covering the head of the penis, most often in men and boys who have not been circumcised
• Penile cancer - a rare form of cancer, highly curable when caught early

The Penis

The penis is the male organ of copulation (sexual intercourse). It is flaccid for non-sexual actions, such as urination, and turgid and rod-like with sexual arousal. When erect, the stiffness of the organ allows it to penetrate into the vagina and deposit semen into the female reproductive tract.

The shaft of the penis surrounds the urethra (Figure). The shaft is composed of three column-like chambers of erectile tissue that span the length of the shaft. Each of the two larger lateral chambers is called a corpus cavernosum (plural = corpora cavernosa). Together, these make up the bulk of the penis. The corpus spongiosum, which can be felt as a raised ridge on the erect penis, is a smaller chamber that surrounds the spongy, or penile, urethra. The end of the penis, called the glans penis, has a high concentration of nerve endings, resulting in very sensitive skin that influences the likelihood of ejaculation (see Figure). The skin from the shaft extends down over the glans and forms a collar called the prepuce (or foreskin). The foreskin also contains a dense concentration of nerve endings, and both lubricate and protect the sensitive skin of the glans penis. A surgical procedure called circumcision, often performed for religious or social reasons, removes the prepuce, typically within days of birth.

Both sexual arousal and REM sleep (during which dreaming occurs) can induce an erection. Penile erections are the result of vasocongestion, or engorgement of the tissues because of more arterial blood flowing into the penis than is leaving in the veins. During sexual arousal, nitric oxide (NO) is released from nerve endings near blood vessels within the corpora cavernosa and spongiosum. Release of NO activates a signaling pathway that results in relaxation of the smooth muscles that surround the penile arteries, causing them to dilate. This dilation increases the amount of blood that can enter the penis and induces the endothelial cells in the penile arterial walls to also secrete NO and perpetuate the vasodilation. The rapid increase in blood volume fills the erectile chambers, and the increased pressure of the filled chambers compresses the thin-walled penile venules, preventing venous drainage of the penis. The result of this increased blood flow to the penis and reduced blood return from the penis is erection. Depending on the flaccid dimensions of a penis, it can increase in size slightly or greatly during erection, with the average length of an erect penis measuring approximately 15 cm.

Disorders of the Male Reproductive System: Erectile Dysfunction (ED)

Erectile dysfunction (ED) is a condition in which a man has difficulty either initiating or maintaining an erection. The combined prevalence of minimal, moderate, and complete ED is approximately 40 percent in men at age 40, and reaches nearly 70 percent by 70 years of age. In addition to aging, ED is associated with diabetes, vascular disease, psychiatric disorders, prostate disorders, the use of some drugs such as certain antidepressants, and problems with the testes resulting in low testosterone concentrations. These physical and emotional conditions can lead to interruptions in the vasodilation pathway and result in an inability to achieve an erection.

Recall that the release of NO induces relaxation of the smooth muscles that surround the penile arteries, leading to the vasodilation necessary to achieve an erection. To reverse the process of vasodilation, an enzyme called phosphodiesterase (PDE) degrades a key component of the NO signaling pathway called cGMP. There are several different forms of this enzyme, and PDE type 5 is the type of PDE found in the tissues of the penis. Scientists discovered that inhibiting PDE5 increases blood flow, and allows vasodilation of the penis to occur.

PDEs and the vasodilation signaling pathway are found in the vasculature in other parts of the body. In the 1990s, clinical trials of a PDE5 inhibitor called sildenafil were initiated to treat hypertension and angina pectoris (chest pain caused by poor blood flow through the heart). The trial showed that the drug was not effective at treating heart conditions, but many men experienced erection and priapism (erection lasting longer than 4 hours). Because of this, a clinical trial was started to investigate the ability of sildenafil to promote erections in men suffering from ED. In 1998, the FDA approved the drug, marketed as Viagra^®. Since approval of the drug, sildenafil and similar PDE inhibitors now generate over a billion dollars a year in sales, and are reported to be effective in treating approximately 70 to 85 percent of cases of ED. Importantly, men with health problems—especially those with cardiac disease taking nitrates—should avoid Viagra or talk to their physician to find out if they are a candidate for the use of this drug, as deaths have been reported for at-risk users.

What is circumcision?

Circumcision is a surgical procedure to remove the foreskin, the skin that covers the tip of the penis. In the United States, it is often done before a new baby leaves the hospital. According to the American Academy of Pediatrics (AAP), there are medical benefits and risks to circumcision.

What are the medical benefits of circumcision?

The possible medical benefits of circumcision include

• A lower risk of HIV
• A slightly lower risk of other sexually transmitted diseases
• A slightly lower risk of urinary tract infections and penile cancer. However, these are both rare in all males.

What are the risks of circumcision?

The risks of circumcision include

• A low risk of bleeding or infection
• Pain. AAP suggests that providers use pain medicines to reduce pain from circumcision.

What are the American Academy of Pediatrics (AAP) recommendations on circumcision?

The AAP does not recommend routine circumcision. However, they said that because of the possible benefits, parents should have the option to circumcise their sons if they want to. They recommend that parents discuss circumcision with their baby's health care provider. Parents should make their decision based on the benefits and risks, as well as their own religious, cultural, and personal preferences.

Erectile dysfunction (ED) is a common type of male sexual dysfunction. It is when a man has trouble getting or keeping an erection. ED becomes more common as you get older. But it's not a natural part of aging.

Some people have trouble speaking with their doctors about sex. But if you have ED, you should tell your doctor. ED can be a sign of health problems. It may mean your blood vessels are clogged. It may mean you have nerve damage from diabetes. If you don't see your doctor, these problems will go untreated.

Your doctor can offer several new treatments for ED. For many men, the answer is as simple as taking a pill. Getting more exercise, losing weight, or stopping smoking may also help.

Infertility is a term doctors use if a man hasn't been able to get a woman pregnant after at least one year of trying. Causes of male infertility include

• Physical problems with the testicles
• Blockages in the ducts that carry sperm
• Hormone problems
• A history of high fevers or mumps
• Genetic disorders
• Lifestyle or environmental factors

About a third of the time, infertility is because of a problem with the man. One third of the time, it is a problem with the woman. Sometimes no cause can be found.

If you suspect you are infertile, see your doctor. There are tests that may tell if you have fertility problems. When it is possible to find the cause, treatments may include medicines, surgery, or assisted reproductive technology. Happily, many couples treated for infertility are able to have babies.

What are sexually transmitted infections (STIs)?

Sexually transmitted infections (STIs), or sexually transmitted diseases (STDs), are infections that are passed from one person to another through sexual contact. They are usually spread during vaginal, oral, or anal sex. But sometimes they can spread through other sexual contact involving the penis, vagina, mouth, or anus. This is because some STIs, like herpes and HPV, are spread by skin-to-skin contact.

Some STIs can be passed from a pregnant person to the baby, either during pregnancy or when giving birth. Other ways that some STIs may be spread include during breastfeeding, through blood transfusions, or by sharing needles.

There are more than 20 types of STIs, including:

• Chlamydia
• Genital herpes
• Gonorrhea
• HIV
• HPV
• Pubic lice
• Syphilis
• Trichomoniasis

What causes sexually transmitted infections (STIs)?

STIs can be caused by bacteria, viruses, and parasites.

Who is affected by sexually transmitted infections (STIs)?

Most STIs affect both men and women, but in many cases the health problems they cause can be more severe for women. If an STI is passed to a baby, it can cause serious health problems.

What are the symptoms of sexually transmitted infections (STIs)?

STIs don't always cause symptoms or may only cause mild symptoms. So it is possible to have an infection and not know it. And even without symptoms, STIs can still be harmful and may be passed on during sex.

If there are symptoms, they could include:

• Unusual discharge from the penis or vagina
• Sores or warts on the genital area
• Painful or frequent urination (peeing)
• Itching and redness in the genital area
• Blisters or sores in or around the mouth
• Abnormal vaginal odor
• Anal itching, soreness, or bleeding
• Abdominal (belly) pain
• Fever

How are sexually transmitted infections (STIs) diagnosed?

If you are sexually active, you should talk to your health care provider about your risk for STIs and whether you need to be tested. This is especially important since many STIs do not usually cause symptoms.

Some STIs may be diagnosed during a physical exam or through STI testing. Some tests involve a microscopic examination of a sore or fluid swabbed from the vagina, penis, or anus. Blood tests can diagnose other types of STIs.

What are the treatments for sexually transmitted infections (STIs)?

Antibiotics can treat STIs that are caused by bacteria or parasites. There is no cure for STIs caused by viruses, but antiviral medicines can often help with the symptoms and lower your risk of spreading the infection.

It's important to get treatment if you have an STI. Some types of STIs can cause serious health problems if they are not treated.

Can sexually transmitted infections (STIs) be prevented?

The surest way to protect yourself against STIs is to not have sex.

If you do decide to have sex, you can lower your risk of getting an STI by:

• Having you and your partner tested for STIs before having sex.
• Using a condom every time you have sex. Correct usage of latex condoms greatly reduces, but does not completely eliminate, the risk of catching or spreading STIs. If your or your partner is allergic to latex, you can use polyurethane condoms.
• Reducing your number of sex partners. You might even consider "mutual monogamy" with just one partner. This means that you agree to be sexually active only with them, and they agree to be sexually active only with you. But first you should both get tested to make sure that you don't already have an STI.
• Getting vaccinated against HPV and hepatitis B.

Testicles, or testes, make male hormones and sperm. They are two egg-shaped organs inside the scrotum, the loose sac of skin behind the penis. You can get cancer in one or both testicles.

Testicular cancer mainly affects young men between the ages of 20 and 39. It is also more common in men who:

• Have had abnormal testicle development
• Have had an undescended testicle
• Have a family history of the cancer

Symptoms include pain, swelling, or lumps in your testicles or groin area. Doctors use a physical exam, lab tests, imaging tests, and a biopsy to diagnose testicular cancer. Most cases can be treated, especially if found early. Treatment options include surgery, radiation, and/or chemotherapy. Regular exams after treatment are important.

Treatments may also cause infertility. If you may want children later on, you should consider sperm banking before treatment.

Although cancer of the testes is rare, accounting for only about 1 percent of all cancers in men of all ages and about 5 percent of all male genitourinary system cancers, it is the most common cancer in men between the ages of 15 and 35, and the second most common malignancy in men ages 35 to 39.

Fortunately, testicular cancer is often curable. The treatment success is due to effective diagnostic methods, including identification of tumor markers; effective combinations of chemotherapy drugs; and improved surgical techniques.

Testicular cancers almost always occur in just one testis rather than both; however, about two to three percent occur in both testes either at the same time or successively. The cancer cells grow rapidly but are very susceptible to chemotherapy and radiation therapy.

Because the incidence of testicular cancer has risen markedly in the past 20 years, numerous studies are being conducted to explore possible environmental causes, including the mother's diet during her pregnancy as well as her use of diethylstilbestrol (DES) to prevent miscarriage. Researchers are also looking at the increasing presence of estrogen-mimicking pollutants in the environment. The most consistent occupational association has been the elevated rate among men in professional and white-collar occupation, which may be linked to an increased risk observed with lower levels of exercise.

Other possible causes include hereditary factors, genetic anomalies, congenital defects involving the reproductive tract, testicular injury, and atrophy of the testes. Viral infections such as mumps, which cause inflammation of the testes, have not been proven to cause cancer.

KEY POINTS

• Testicular cancer is a disease in which malignant (cancer) cells form in the tissues of one or both testicles.
• Health history can affect the risk of testicular cancer.
• Signs and symptoms of testicular cancer include swelling or discomfort in the scrotum.
• Tests that examine the testicles and blood are used to diagnose testicular cancer.
• Certain factors affect prognosis (chance of recovery) and treatment options.
• Treatment for testicular cancer can cause infertility.

Testicular cancer is a disease in which malignant (cancer) cells form in the tissues of one or both testicles.

The testicles are 2 egg-shaped glands located inside the scrotum (a sac of loose skin that lies directly below the penis). The testicles are held within the scrotum by the spermatic cord, which also contains the vas deferens and vessels and nerves of the testicles.

The testicles are the male sex glands and produce testosterone and sperm. Germ cells within the testicles produce immature sperm that travel through a network of tubules (tiny tubes) and larger tubes into the epididymis (a long coiled tube next to the testicles) where the sperm mature and are stored.

Almost all testicular cancers start in the germ cells. The two main types of testicular germ cell tumors are seminomas and nonseminomas. These 2 types grow and spread differently and are treated differently. Nonseminomas tend to grow and spread more quickly than seminomas. Seminomas are more sensitive to radiation. A testicular tumor that contains both seminoma and nonseminoma cells is treated as a nonseminoma.

Testicular cancer is the most common cancer in men 20 to 35 years old.

Health history can affect the risk of testicular cancer.

Anything that increases the chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Risk factors for testicular cancer include:

• Having had an undescended testicle.
• Having had abnormal development of the testicles.
• Having a personal history of testicular cancer.
• Having a family history of testicular cancer (especially in a father or brother).
• Being White.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• Stage of the cancer (whether it is in or near the testicle or has spread to other places in the body, and blood levels of AFP, beta-hCG, and LDH).
• Type of cancer.
• Size of the tumor.
• Number and size of retroperitoneal lymph nodes.

Testicular cancer can usually be cured in patients who receive adjuvant chemotherapy or radiation therapy after their primary treatment.

Treatment for testicular cancer can cause infertility.

Certain treatments for testicular cancer can cause infertility that may be permanent. Patients who may wish to have children should consider sperm banking before having treatment. Sperm banking is the process of freezing sperm and storing it for later use.

• Testicular cancer is the most common cancer in males between the ages of 15 and 35.
• Testicular cancer is the second most common malignancy in men ages 35 to 39.
• Testicular cancer is often curable.
• Cancer cells of testicular cancer grow rapidly, but are usually very susceptible to chemotherapy and radiation therapy.
• Lower levels of exercise are believed to be linked to increased risk of testicular cancer.
• Other possible risk factors include heredity, genetic abnormalities, congenial defects in the reproductive tract, testicular injury, and atrophy of the testes.
• Ninety-five percent of testicular cancers arise from sperm-forming, or germ, cells and are called germinal tumors; the remaining 5 percent are nongerminal tumors.
• Germ cells become malignant at a very early stage in their development, and they may be anaplastic, classic (or typical), or spermatocytic, depending on their origin.
• Cells more mature and specialized than the germ cells give rise to nonseminomas.
• Testicular cancers tend to spread through the spermatic cord and associated blood and lymph vessels into local lymph glands called the retroperitoneal lymph nodes.
• Signs and symptoms of testicular cancer include testicular pain, acute epididymitis, night sweats and fever, weight loss, abdominal pain.

The absence of GONADS in an XY person. In most cases, uterus and fallopian tubes are absent but small tubular structures interpreted as mullerian or wolffian duct rudiments (or both) are present. Virilizing effects due to early testicular tissue range from none or very slight external genital abnormalities in phenotypic females to the anorchic phenotypic male . Most affected individuals lack a vagina but a urogenital sinus or pseudovaginal urethral outpouching is found. Partial labioscrotal fusion and clitoris enlargement are common but breast development is absent. Nongenital anomalies may also be present. Inheritance appears to be autosomal recessive with sex limitation.

Accumulation of serous fluid between the layers of membrane (tunica vaginalis) covering the TESTIS in the SCROTUM.

Introduction

A hydrocele is an abnormal collection of serous fluid between the two layers of tunica vaginalis of testis. It can either be congenital or acquired.

Congenital hydrocele results from failure of processus vaginalis to obliterate. During development, the testes are formed retroperitoneally in the abdomen and proceed to descend into the scrotum via the inguinal canal in the third gestational week. This descent of the testes into the scrotum is accompanied by a fold of peritoneum of the processus vaginalis. Normally, the proximal portion of processus vaginalis gets obliterated while the distal portion persists as the tunica vaginalis covering the anterior, lateral, and medial aspects of the testes. The tunica vaginalis is a potential space for fluid to accumulate, provided the proximal portion of processus vaginalis remains patent and results in free communication with the peritoneal cavity, leading to congenital hydrocele.

Hydroceles are divided into two types: primary and secondary.

• Primary Hydrocele: The processus vaginalis of the spermatic cord fuses at term or within 1-2 years of birth, thus obliterating the communication between the abdomen and scrotum. The distal portion, however, remains patent as the tunica vaginalis covers the testis, creating a potential space where fluid accumulation within it can lead to hydrocele formation. Depending upon the site of the obliteration of processus vaginalis, there are four types of primary hydrocele.1. Congenital Hydrocele: Thisoccurs when processus vaginalis is patent and communicates with the peritoneal cavity. This communication allows the movement of peritoneal fluid but is too small to allow the intra-abdominal contents to herniate through.2. Infantile Hydrocele: In this case, processus vaginalis gets obliterated at the level of the deep inguinal ring. However, the portion distal to it remains patent and allows fluid accumulation.3. Encysted Hydrocele of the Cord: Both the proximal and distal portions of processus vaginalis get obliterated while the central portion remains patent and fluid accumulates within it.4. Vaginal Hydrocele: Processus vaginalis remains patent only around the testes, and, as fluid accumulates, it renders the testes impalpable.
• Secondary Hydrocele: This usually occurs as a result of an underlying condition, such as infection (filariasis, tuberculosis of the epididymis, syphilis), injury (trauma, post-herniorrhaphy hydrocele), or malignancy. This type of hydrocele tends to be small, with the exception of secondary hydrocele due to filariasis, which can be very large.

Etiology

There are four basic mechanisms by which hydrocele can develop. These are mentioned below:1. Connection with the peritoneal cavity through a patent processes vaginalis (congenital).2. Excessive production of fluid (secondary hydrocele).3. Defective absorption of fluid. 4. Interference with the lymphatic drainage of scrotal structures as in filarial hydroceles. In children, patency of processus vaginalis, allowing peritoneal fluid to flow into the scrotum, is the main cause of hydrocele. However, in adults, filariasis caused by Wuchereria bancroftiis the main culprit globally, affecting 120 million people in more than 73 countries.[3] This is not true in the United States, where iatrogenic causes (either trauma or post-herniorrhaphy complications) predominate.

Epidemiology

At birth, around 80-90% of term male infants possess a patent processus vaginalis. This figure declines steadily to settle at approximately 25-40% at two years of age.

Autopsy data indicates that processus vaginalis tends to remain patent at a frequency of 20% until later in adult life. However, only 6% of these become clinically evident beyond the newborn period. Risk factors of hydrocele include breech presentation, low birth weight, and gestational progestin use.

History and Physical

The majority of patients with hydrocele present with the complaint of painless scrotal swelling rendering the testes impalpable with positive transillumination and fluctuation. The examiner should look at this swelling in both the supine and upright positions. During the examination, the provider should ask the following set of three questions:

1. Is it possible to reach above the swelling and palpate the cord? If no, this could represent a hydrocele (congenital or infantile) or a hernia. A hernia can be differentiated from hydrocele in terms of having expansile cough impulse and reducibility but lacking transillumination and fluctuation.

2. Does the swelling arise from testis or epididymis or encase both of these structures. Hydroceles tend to surround both testes and epididymis, rendering them impalpable.

3. Does the swelling transilluminate?

The primary hydrocele is predominant in middle and later life. A common predisposing factor for hydrocele is residing in a warm climate. As it is painless, it acquires a prodigious size before the patient seeks medical attention. In contrast, the secondary hydrocele is generally smaller, with the exception of filarial hydrocele.

Congenital hydrocele tends to be intermittent as it usually reduces when lying flat due to drainage of hydrocele fluid into the peritoneum. However, applying pressure on the congenital hydrocele does not reduce it.

An encysted hydrocele feels like a smooth oval-shaped swelling near the spermatic cord. It may feel like an inguinal hernia and therefore, should be differentiated. In female patients, the hydrocele of the canal of Nuck is a rare condition in which a cyst develops anterior to the round ligament of the uterus.

Evaluation

Hydroceles can be diagnosed on clinical grounds, as discussed in the history and physical section. However, in the presence of any concomitant medical condition or to exclude other medical or surgical conditions, further studies, including laboratory or imaging, should be considered.

Laboratory Studies

These are indicated to exclude other surgical or medical conditions that may be in the differential diagnosis.

• Inguinal Hernia: Laboratory tests are usually not indicated, but in the case of an incarcerated inguinal hernia, which can mimic hydrocele, leukocytosis can aid in the differentiation. Negative transillumination and palpable bowel at the deep ring on the digital examination is more consistent with an inguinal hernia.
• Testicular Tumor: Serum alpha-fetoprotein and human chorionic gonadotropin (hCG) levels are indicated if there is suspicion of malignant teratomas or other germ cell tumors.
• Epididymitis/Orchitis: These conditions can lead to secondary or reactive hydroceles. In such cases, urinalysis and urine culture may be useful.

Imaging Studies

These are helpful in diagnosing and evaluating hydrocele. They can also assess for underlying processes such as epididymitis, testicular torsion, or testicular tumor.

Ultrasonography: Scrotal pain or failure to delineate the testicular anatomy on palpation is an indication for ultrasonography as it provides excellent detail of testicular parenchyma. During the ultrasonography examination, hydrocele appears as an anechoic or echolucent area surrounding the testis. Ultrasonography could also help with the sizing and characterization of the hydrocele. Spermatoceles, testicular tumors, and testicular atrophy can be easily distinguished via ultrasonography. The patient should be examined in both supine and upright positions as hydrocele has a tendency to reduce into the abdomen based on the position of the patient.

Duplex Ultrasonography: It provides information regarding testicular blood flow, which will be reduced or absent in hydroceles resulting from testicular torsions. However, in the case of hydroceles secondary to epididymitis, the epididymal flow would be increased. In addition, duplex studies help identify the Valsalva augmented regurgitant flow in varicoceles.

Plain Abdominal Radiography: In an incarcerated inguinal hernia, one may see gas overlying the groin.

Treatment / Management

Surgery is the treatment of choice for hydrocele, and it is warranted when hydrocele becomes complicated or symptomatic. For congenital hydroceles, herniotomy is performed, provided they do not resolve spontaneously. On the other hand, acquired hydroceles subside when the primary underlying condition resolves.

There are two common surgical approaches available for hydrocelectomy:

1. Plication: This technique is suitable for thin-walled hydroceles. As there is minimal dissection, the risk of hematocele or infection is significantly reduced. Lord plication involves the tunica being bunched into a ruff by applying a series of multiple interrupted chromic catgut sutures for the sac to form fibrous tissue.

2. Excision and Eversion: This technique is suitable for large thick-walled hydroceles and chyloceles. It involves subtotal excision of the tunica vaginalis and everting the sac behind the testes followed by placing the testes in a newly created pocket between the fascial layers of the scrotum (Jaboulay procedure). Particular consideration is taken not to damage epididymis, testicular vessels, or ductus deferens.

Aspiration

This is another method to treat hydrocele, particularly in patients who cannot tolerate surgery. However, hydrocele fluid almost always reaccumulates within a week or so. In addition, the risk of hematocele and infection after aspiration is high. Aspiration followed by an injection of a sclerosant (tetracycline or doxycycline) has been proven to be effective but painful.

Complications of Surgery

• Reactionary hemorrhage
• Pyocele
• Infection
• Sinus formation
• Recurrent hydrocele

Differential Diagnosis

Differential diagnoses of hydrocele include:

• Inguinal hernia
• Epididymal cyst
• Spermatocele
• Testicular tumor
• Scrotal edema
• Varicocele

Prognosis

The prognosis of the congenital hydrocele is excellent, while that of the adult-onset hydrocele depends on the underlying cause.

Congenital hydroceles tend to resolve spontaneously by the end of the first year of life. If persistent, they can be corrected surgically with a high success rate and a good long-term prognosis. In experienced hands, hydrocele repair carries a very low risk of testicular damage or recurrence.

The prognosis of the adult-onset hydrocele is mainly dependent on the underlying cause. For instance, filarial hydrocele's prognosis depends on its size and the severity of lymphatic obstruction.

Complications

Complications are attributable to the pathology itself and the treatment administered. Some of them are as follows:

• Infection
• Pyocele
• Haematocele
• Atrophy of testes
• Infertility (resulting from the spermatogenesis halt due to increased pressure on the blood supply on the testis from edema)
• Rupture
• Hernia of hydrocele (rare)

Deterrence and Patient Education

Although hydroceles in infants tend to resolve spontaneously, they need to be monitored closely. In this regard, parents play a vital role. If such hydroceles persist beyond two years of age, a surgeon should be approached for its management. Parental anxiety is common, so they need to be counseled properly. In adults, hydroceles without underlying pathology can be self-monitored regarding its size or any component of infection. However, in cases of hydroceles resulting from an underlying condition, medical attention should be sought to avoid any morbidity or mortality.

Patients should be made aware of the complications of hydrocele. Also, all the treatment options should be discussed thoroughly with the patient. The patient should be educated that, despite proper medical or surgical management, the hydrocele may recur.

Enhancing Healthcare Team Outcomes

Congenital hydroceles mostly resolve before two years of age. Therefore, parents of such patients should be properly counseled to curb their anxiety. In this regard, providers and nursing staff play a vital role. If hydrocele develops later in life, underlying pathology must be identified as its prognosis is dependent on it. For this purpose, coordination among radiologists, pathologists, and surgeons is vital for better patient outcomes. The nursing staff is also a significant segment of the interprofessional group as they assist in educating the patient and family members regarding the disease. This type of interprofessional collaboration is the key to achieving optimal patient outcomes in the case of hydroceles.

Condition resulting from deficient gonadal functions, such as GAMETOGENESIS and the production of GONADAL STEROID HORMONES. It is characterized by delay in GROWTH, germ cell maturation, and development of secondary sex characteristics. Hypogonadism can be due to a deficiency of GONADOTROPINS (hypogonadotropic hypogonadism) or due to primary gonadal failure (hypergonadotropic hypogonadism).

Inflammation of a TESTIS. It has many features of EPIDIDYMITIS, such as swollen SCROTUM; PAIN; PYURIA; and FEVER. It is usually related to infections in the URINARY TRACT, which likely spread to the EPIDIDYMIS and then the TESTIS through either the VAS DEFERENS or the lymphatics of the SPERMATIC CORD.