Male Genitalia and Hernias

General Considerations

Since the beginning of recorded history, the external genitalia and the urologic system have been of special interest to people. Kidney stones and urologic surgery were well described in antiquity. One of the earliest reported kidney stones was found in a young boy who lived about 7000 BCE.

Circumcision is one of the oldest known surgical procedures in medicine. Male circumcision has been widely practiced as a religious rite since ancient times. An initiatory rite of Judaism, circumcision is practiced also by Muslims for whom it signifies spiritual purification. Although the origin is unknown, circumcision is often depicted on the walls of temples dating from 3000 BCE. In the Egyptian Book of the Dead, it is written, “The blood falls from the phallus of the Sun God as he starts to incise himself.” By the time of the Roman takeover of Egypt in 30 BCE, the practice of circumcision had a ritual significance, and only circumcised priests could perform certain religious rites. The Hindus regarded the penis and testicles as a symbol of the center of life and sacrificed the prepuce as a special offering to the gods.

The Bible has many urologic references. In Genesis 17 : 7, Abraham makes a covenant with God for the Jews. He is told in Genesis 17 : 14, “And the uncircumcised male who is not circumcised in the flesh of his foreskin, that soul shall be cut off from his people; he hath broken My covenant.” In Leviticus 12 : 3, the Jews were told, “And in the eighth day the flesh of his foreskin shall be circumcised.” Leviticus 15 : 2-17 deals with discharges that render a man unclean. Today, it is estimated that one in every six men worldwide is circumcised. There are more than 15 million postinfancy circumcisions a year, and thus it is one of the most common surgical procedures.

The Bible, Hindu literature, and Egyptian papyri described a disease now presumed to be gonorrhea. The Mesopotamian tablets described a variety of cures, such as this: “If a man's penis on occasions of his pleasure hurts him, boil beer and milk and anoint him from the pubis.” Avicenna's Canon of Medicine (1000 CE) was considered the authoritative medical text for centuries and described placing a louse in the penis to counteract a penile discharge.

Gonorrhea was probably first named by Galen in the second century CE. Gonorrhea is the Greek translation of “a flow of offspring.” Galen apparently thought that the purulent discharge was a leakage of semen. Many terms have been used to describe gonorrhea throughout the years. Perhaps the most common is clap, a name used for the past 400 years. It is thought that the term clap was derived from a specific area in Paris known for prostitution called Le Clapier.

It is unclear when the scourge of syphilis began. There was much confusion between syphilis and gonorrhea. It was thought that gonorrhea was the first stage of syphilis. The cause of these diseases was also unknown. Many believed that syphilis was caused by floods, eating disguised human meat, or drinking poisoned water. It was not until 1500, when syphilis was pandemic in Europe, that the venereal origins of both diseases were understood. It is now believed that syphilis was introduced on the European continent in 1492 by the returning sailors who had been traveling with Columbus. After France's invasion of Italy and the siege of Naples in 1495, syphilis became rampant throughout Europe. The King's pox and the French pox were common terms for syphilis.

Benign prostatic hyperplasia (BPH) is the most common benign neoplasm in aging men. It has been estimated that by 60 years of age, the prevalence is greater than 50%, and by 85 years of age, the prevalence approaches 90%. In addition, by 80 years of age, one in every four men requires some form of treatment for relief of symptomatic BPH. More than 300,000 surgical procedures are performed in the United States annually for BPH, most commonly a transurethral resection of the prostate (TURP).

Cancer of the genitourinary system is common. In the United States, in 2018, prostate cancer accounted for 19% of all cancer cases in men. It accounted for 9% of all cancer deaths and was the second most common cause of cancer deaths after lung and bronchus cancer (26%). In 2018, there were 164,690 new cases of prostate cancer and 29,430 deaths from the disease in the United States. For further discussion of cancer of the prostate, see Chapter 17 , The Abdomen.

Cancer of the urinary bladder accounted for an additional 7% of cancer cases; only 4% of all cancer deaths in men and less than 1% in women. In 2018, there were 81,190 new cases (62,380 in men and 18,810 in women) of cancer of the urinary bladder in the United States and 17,240 deaths from the disease. Approximately 275,000 new cases of urinary bladder cancer are diagnosed worldwide every year. The highest incidence rates for bladder cancer are found in industrialized countries such as the United States, Canada, France, Denmark, Italy, and Spain. The lowest rates are in Asia and South America, where the incidence is only approximately 30% as high as in the United States. Cigarette smoking is an established risk factor for cancer of the urinary bladder. It is estimated that approximately 50% of these cancers in men and 30% in women are linked to smoking. Occupational exposures may account for up to 25% of all urinary bladder cancers. Most of the occupationally accrued risk is attributable to exposure to a group of chemicals known as arylamines. Occupations with high exposure to arylamines include dye workers, rubber workers, leather workers, truck drivers, painters, and aluminum workers. People who live in communities with high arsenic levels in the drinking water also have an increased risk of urinary bladder cancer.

Although testicular cancer accounts for only 1% of all cancers in men, testicular carcinoma is the most common cancer in men in the 18- to 35-year-old age group. There were 9310 new testicular cancer cases in 2018 and 400 related deaths. Testicular cancer is four times less common in African American men than in white men. The risk for development of testicular cancer in a man's lifetime is approximately 1 per 500. Approximately 90% of all testicular tumors manifest as an asymptomatic testicular mass. Once these tumors are detected and treatment is begun, the cure rate can approach 90%, even when the tumor has spread beyond the testicle. Many patients have oligospermia or sperm abnormalities before therapy. Virtually all become oligospermic during chemotherapy with platinum-based agents. Many recover sperm production, however, and can father children, often without the use of cryopreserved semen. In a population-based study, 70% of patients actually fathered children. Men in whom testicular cancer has been cured have approximately a 2% to 5% cumulative risk of developing a cancer in the opposite testicle during the 25 years after initial diagnosis. The most important prognostic factor has been shown to be early detection by routine physical examination and self-examination. All men should be instructed in testicular self-examination.

There were 65,340 new cases of renal cancer in 2018. These included 92% renal cell carcinoma, 7% renal pelvis carcinoma, and 1% Wilms tumor, a childhood cancer that develops before the age of 5 years. The American Cancer Society reported 14,970 deaths from all types of renal cancer in the United States. Tobacco use is a strong risk factor for renal cancer with the largest increased risk for cancer of the renal pelvis, particularly in heavy smokers.

Erectile dysfunction (ED) is an extremely common problem. It has been estimated that more than 30 million American men have some degree of ED and that nearly a million new cases can be expected to develop annually. Studies have shown that ED affects not only a man's physical and sexual satisfaction but also his general quality of life, with especially strong links to depression. In the Massachusetts Male Aging Study, 52% of men from 40 to 70 years of age had some degree of ED. Seventeen percent reported minimal dysfunction, 25% reported moderate dysfunction, and 10% reported complete dysfunction. This study also revealed the progressive nature of ED with increasing age. At 40 years of age, 5% of the American male population has complete ED, and at 70 years of age, 15% of the population has complete ED. Sixty-seven percent of men aged 70 years have some degree of ED. As the population continues to age, clinicians will treat more and more male patients for ED in the future.

Structure and Physiologic Characteristics

Cross-sectional and frontal views of the male genitalia are shown in Fig. 18.1 .

The penis is composed of three elongated, distensible structures: two paired corpora cavernosa and a single corpus spongiosum. The urethra runs through the corpus spongiosum. The penis has two surfaces, dorsal and ventral (urethral), and consists of the root, the shaft, and the head. The shaft is composed of erectile tissue that, when engorged with blood, produces a firm erection necessary for sexual intercourse. The corpora cavernosa also contain smooth muscle that contracts rhythmically during ejaculation.

On the dorsal aspect of the penis in the midline runs the dorsal vein, with an artery and a nerve on either side. The distal end of the corpus spongiosum expands to form the head, or glans penis. The glans penis covers the end of the corpora cavernosa. The glans has a prominent margin on its dorsal aspect, the corona. A slit-like opening on the tip of the glans is the external meatus of the urethra.

The skin of the penis is smooth, thin, and hairless. At the distal end of the penis, a free fold of skin called the prepuce (foreskin) covers the glans. Secreted mucus and sloughed epithelial cells called smegma collect between the prepuce and the glans, providing a lubricant during sexual intercourse. The prepuce can be retracted to expose the glans as far as the corona. During circumcision, the prepuce is removed.

The root of the penis lies deep to the scrotum, in the perineum. At the root, the corpora cavernosa diverge. Each corpus cavernosum is enveloped in a dense, fibroelastic covering called the tunica albuginea, and these tunicae fuse to form the median septum of the penis. A cross section through the penis is shown in Fig. 18.2 .

The blood supply to the penis is from the internal pudendal artery, from which the dorsal and deep arteries of the corpora cavernosa are derived. The veins drain into the dorsal vein of the penis. In the flaccid state, the venous channels and arteriovenous anastomoses are widely patent, whereas the arteries are partially constricted.

Erection is a complex hemodynamic and neurophysiologic event. In the flaccid state, the smooth muscles of the penile arteries and sinusoid spaces are contracted. The erectile state begins in the brain and requires relaxation of the smooth muscles of the penis. From the brain center, neural signals are sent to the corpora cavernosa, where synthesis and release of the neurotransmitter nitric oxide occur. Nitric oxide is the primary mediator responsible for endothelial and cavernous smooth muscle relaxation. Nitric oxide activates guanylate cyclase to produce cyclic guanosine monophosphate (GMP), which decreases intracellular calcium levels, allowing smooth muscle relaxation and an increase in arterial inflow and corporal veno-occlusion in the penis. Venous outflow is decreased because distention of the blood-filled sinusoidal spaces compresses the veins against the inner layer of the rigid tunica albuginea. In the erect state, the arteriovenous channels are closed, and the arteries are widely opened. Muscular pillars are present in the walls of the arteries, veins, and arteriovenous anastomoses, which aid in occluding the lumina. Phosphodiesterase, predominantly type V in penile tissue, catalyzes the conversion of cyclic GMP to GMP and results in detumescence. There are oral medications, such as sildenafil (Viagra®), that selectively inhibit phosphodiesterase V, allowing the corpus cavernosum smooth muscle to relax and potentiating erections during sexual stimulation. These agents enhance the effect of the nitric oxide–mediated increase in cyclic GMP levels and significantly improve erectile function and sexual function. The anatomy of erection is illustrated in Fig. 18.3 .

The urethra extends from the internal urinary meatus of the bladder to the external meatus of the penis. The urethra can be divided into three portions: the prostatic (posterior) portion, the membranous portion, and the cavernous (anterior) portion. The short posterior portion passes through the prostate gland. The common ejaculatory duct and several prostatic ducts enter at the distal end of this portion. The external urethral sphincter surrounds the membranous urethra, and on either side lie Cowper bulbourethral glands. The anterior urethra is the longest portion and passes through the corpus spongiosum. The ducts of Cowper glands enter the anterior urethra near its proximal end.

The scrotum is the pouch containing the testes; it is suspended externally from the perineum. The scrotum is divided into halves by the intrascrotal septum, one testis lying on each side. The wall of the scrotum contains involuntary smooth muscle and voluntary striated muscle. A major role of the scrotum is temperature regulation of the testes. The testes are maintained at approximately 2°C lower than the temperature of the peritoneal cavity, a condition necessary for spermatogenesis. The size of the scrotum is variable according to the individual and his response to ambient temperature. During exposure to cold temperatures, the scrotum is contracted and very rugate. In a warm environment, the scrotum becomes pendulous and smoother.

The testes, or testicles, are ovoid, smooth, and approximately 1.5 to 2 inches (3.5 to 5 cm) in length. The left testicle commonly lies lower than the right. The testes are covered with a tough fibrous coat called the tunica albuginea testis. Each testicle has a long axis directed slightly anteriorly and upward and contains long, microscopic, convoluted seminiferous tubules that produce sperm. The tubules end in the epididymis, which is comma-shaped and located on the posterior border of the testis. It consists of a head that is swollen and overhangs the upper pole of the testicle. The inferior portion, or tail, of the epididymis continues into the vas deferens. The testicular artery enters the testicle in its posterior midportion. The veins draining the testicle form a dense network called the pampiniform plexus, which drains into the testicular vein. The right testicular vein drains directly into the inferior vena cava, whereas the left drains into the left renal vein. The lymphatic drainage of the testes is to the preaortic and precaval nodes, not to the inguinal nodes. This is important to recognize because the testes are embryologically intra-abdominal organs, and neoplasms and inflammations of the testis produce adenopathy of these nodal chains. In general, inguinal adenopathy is rare.

The relationship of the testicle and epididymis is illustrated in Fig. 18.4 .

The vas deferens is a cord-like structure, easily felt in the scrotum. The vas deferens, testicular arteries, and veins form the spermatic cord, which enters the inguinal canal. The vas deferens passes through the internal ring and, after a convoluted course, reaches the fundus of the bladder. It passes between the rectum and the bladder and approaches the vas deferens of the opposite side near the seminal vesicles. Near the base of the prostate, the vas deferens joins with the duct of the corresponding seminal vesicle to form the ejaculatory duct, which passes through the prostate gland to enter the posterior urethra.

The prostate gland is approximately the size of two almonds, or approximately 1.5 inches (3.5 cm) long by 1.2 inches (3 cm) wide. Traversing the gland in the midline is the posterior urethra. On either side is an ejaculatory duct. The prostate is commonly divided into five lobes. The posterior lobe is clinically important because prostate carcinoma frequently affects this lobe. In the presence of cancer, the midline groove between the two lateral lobes may be obliterated. The middle and lateral lobes are above the ejaculatory ducts and are typically involved in benign hypertrophy. The anterior lobe is of little clinical importance.

The sources and direction of seminal fluid flow in the male genitalia are illustrated in Fig. 18.5 .

The descent of the testes is important to review. In the normal full-term male newborn, both testes are in the scrotum at birth. The testes descend to this position just before birth. At approximately the 12th week of gestation, the gubernaculum develops in the inguinal fold and grows through the body wall to an area that will ultimately lie in the scrotum. This tract marks the location of the future inguinal canal. A dimple called the processus vaginalis forms in the peritoneum and follows the course of the gubernaculum. By the seventh month of gestation, the processus vaginalis has reached the aponeurosis of the external oblique muscle. Each testis then begins its descent from the abdominal cavity through the internal ring to lie in the abdominal wall. During the eighth month, the testes descend along the inguinal canal; at birth, they are in the scrotum. At birth, the gubernaculum is barely distinguishable, and the processus vaginalis becomes obliterated within the spermatic cord. In approximately 5% of male infants, there is imperfect descent of the testis (cryptorchidism) . The descent of the testes is illustrated in Fig. 18.6 .

The genital development stages for boys are illustrated in Fig. 24.48 (and discussed in Chapter 24 , The Pediatric Patient).

Review of Specific Symptoms

The most common symptoms of male genitourinary disease are as follows:

• Pain

• Dysuria

• Changes in urine flow

• Red urine

• Penile discharge

• Penile lesions

• Genital rashes

• Scrotal enlargement

• Groin mass or swelling

• ED

• Infertility

Penile Discharge

Discharge from the penis is a continuous or intermittent flow of fluid from the urethra. Ask the patient whether he has ever had a discharge and, if he has, whether it was bloody or purulent. Bloody penile discharges are associated with ulcerations, neoplasms, or urethritis. Purulent discharges are thick and yellowish-green and may be associated with gonococcal urethritis or chronic prostatitis. Determine when the discharge was first noted. Fig. 18.7 shows a purulent penile discharge in a man with gonococcal urethritis. Gonorrhea is caused by Neisseria gonorrhoeae. After exposure, approximately 25% of men and more than 50% of women contract the disease. In men, the acute symptoms of dysuria and a purulent urethral discharge begin 2 to 10 days after exposure. In women, a vaginal discharge and dysuria develop days to weeks after exposure; however, in up to 50% of women, the infection may be asymptomatic.

Tactful direct questioning about any history of or exposure to sexually transmitted diseases is essential. The interviewer should determine the patient's sexual orientation ²

2 See Chapter 5 , Deconstructing Racism and Bias in Clinical Medicine.

and the type of sexual exposure—oral, vaginal, or anal—because this information can help determine the types of bacteriologic cultures necessary. Asking direct questions about specific sexual practices (e.g., “Do you have anal intercourse?”) is preferable to asking a more open-ended question (e.g., “In what type of sexual practices do you partake?”). It is appropriate to ask whether the patient has more than one sexual partner and whether the partner(s) have any known illnesses. Make no assumption about the gender of the partner(s). The sexual history questions suggested in Chapter 1 , The Interviewer's Questions, and in Chapter 5 , Deconstructing Racism and Bias in Clinical Medicine, may be helpful.

Genital Rashes

Male genital rashes are very common. They may be confusing to identify and are often difficult to treat. Some rashes may occur exclusively on the genitalia; others, which are typically found on other parts of the body, have an atypical appearance when present on the genitalia. The skin over the genitalia is thin and moist, so typical dry scaliness may not be present.

The most common inflammatory reaction affecting the male genitalia is psoriasis. The patient develops bright red, well-defined, scaling plaques. Often the entire scrotum, inguinal folds, and penis are involved. The penis is a common location for psoriasis and, in some cases, is the sole area of involvement. Psoriatic lesions on the penis are typically red, scaly papules or raised plaques on the glans and shaft, with the exception of uncircumcised men who often experience no scaliness when lesions are located on the glans. Psoriatic patches on other body parts usually facilitate the diagnosis. Supportive findings include red scaly plaques on the elbows, knees (see Fig. 8.53 ), gluteal cleft (see Fig. 8.54 ), scalp (see Fig. 8.56 ), and periumbilicus, as well as pitting of the nail plates (see Fig. 8.14 ). Fig. 18.8 shows psoriasis of the penis.

Another form of genital rash is contact dermatitis. It may develop from soaps or disinfectants. Irritants used for facial actinic keratosis may inadvertently be transferred to the genitalia. Itching is a major symptom.

Fixed drug eruptions are unique reactions that appear in the same area of the body each time the responsible drug is given. Fixed drug reactions manifest as a sudden onset of multiple, well-defined, macular, eczematous, bullous patches. When the genitalia are involved, these eruptions typically occur on the distal penis and glans and may be very painful. Drugs known to cause these eruptions include nonsteroidal antiinflammatory drugs, sulfonamides (especially co-trimoxazole), and laxatives containing phenolphthalein, tetracycline, and barbiturates. Fig. 18.9 shows a fixed drug reaction after taking tetracycline. More than 500 medications have been implicated in fixed drug reactions; therefore, the examiner should take a careful medication history.

Lichen planus is an inflammatory disorder characterized by violaceous, flat, shiny papules ranging from 0.75 to 3 inches (2 to 8 mm) in diameter that are faintly erythematous to violet in color. The glans penis is frequently involved. Typical penile lichen planus is asymptomatic and commonly resolves with residual hyperpigmentation. An oral examination may also reveal the classic serpiginous white streaks on the buccal mucosa (see Fig. 12.15 ). Fig. 18.10 shows lichen planus of the penis.