The Male Genital System

Chapter 16 The Male Genital System



Ivan Damjanov, MD, PhD




1 What are the principal male genital organs?



image Testis

image Epididymis

image Vas deferens

image Seminal vesicles

image Prostate

image Penis

image Scrotum


2 What are the most important diseases of the male genital system?



image Developmental disorders

image Infections

image Infertility

image Tumors


Key Points: Diseases of the Male Genital System



1. The most important diseases of the male genital system are infections and tumors.

2. Developmental disorders of the male genital system may have adverse effects on fertility or predispose to infections.

3. In young men, infections of the male genital system are mostly sexually transmitted, whereas in older men they are due to prostatic disease.


DEVELOPMENTAL DISORDERS



3 What is the most common developmental abnormality involving the testis?


Cryptorchidism is the most common abnormality of the male genital tract. It is found in 3% of full-term infants but is much more common in prematurely born boys. It results from an incomplete descent of the testis into the scrotum. The testis may be “hidden” (as the term implies, cryptos, meaning “hidden” in Greek) in the abdominal cavity or inside the inguinal canal. Such testes can be repositioned into the scrotum surgically (“orchidopexy”).



4 What are the complications of cryptorchidism?


Cryptorchidism is associated with an increased incidence of:


image Infertility: The testis retained in the abdominal cavity or the inguinal canal undergoes atrophy, and the seminal epithelium degenerates.

image Germ cell tumors: The reasons for the increased incidence of germ cell tumors are not known.


5 What is the difference between hypospadias and epispadias?


The urethral meatus is normally located at the tip of the penis. The anomaly in which the opening of the urethra is found on the ventral surface of the penile shaft is called hypospadias. Opening of the penile urethra on the dorsal surface of the penis is called epispadias. Hypospadias is more common (1:1000 newborn males) than epispadias (1:30,000 newborn males). Hypospadias is a less severe anomaly, and it usually occurs in an isolated form. Epispadias often involves a longer segment of the penis and is often combined with extrophy of the urinary bladder. See Fig. 16-1.


image

Figure 16-1 Developmental disorders of penile urethra. A, Normal. B, Hypospadia. C, Epispadia.


(From Price SA, Wilson LM: Pathophysiology: Clinical Concepts of Disease Processes, 6th ed. St. Louis, Mosby, 2003, p. 988.)



6 What is phimosis?


Phimosis is an abnormality of the penis characterized by tight prepuce (foreskin) that cannot be retracted over the glans penis. Phimosis can be congenital or secondary to infections causing fibrosis of the foreskin. Circumcision is the treatment of choice.



7 What is paraphimosis?


Paraphimosis is a condition in which a tight prepuce is retracted over the glans but cannot be rolled back, thus strangulating the glans penis.



8 What is inguinal scrotal hernia?


Following the descent of the testis, the inguinal canal closes. If the canal remains open, abdominal contents can slide through the inguinal canal into the scrotum, resulting in a hernia. Hernia may be congenital or acquired because of a reopening of a previously closed inguinal canal.



9 What is a hydrocele?


A hydrocele is an accumulation of fluid in the scrotum, typically between the two layers of tunica vaginalis testis. This tunica is an extension of the mesothelium that envelops the testis during its descent.


Normally the surfaces of tunica are kept wet with a few drops of fluid. Occasionally the amount of fluid will increase, often for no obvious cause. Similar hydrocele may develop because of infection of the testis and epididymis or due to a blockade of lymphatic drainage from the scrotum. Fluid also accumulates in the scrotum in generalized anasarca and also in the course of heart failure.



10 What are the other scrotal disorders that may be confused with hydrocele?


Hydrocele is diagnosed by palpating the scrotum and testes and by documenting fluid accumulation in the spaces limited by tunica vaginalis testis. This is best achieved by transluminating the scrotal contents with a flashlight placed behind the scrotum. Other conditions that may be mistaken for hydrocele are:


image Epididymal cysts: These cysts represent developmental recesses attached to the epididymis. If filled with sperm, they are called spermatocele.

image Scrotal hernia: Loops of the intestine may slide into the scrotum and present as a scrotal mass.

image Varicocele: This term is used for the varicous dilatation of the scrotal veins (“bag of worms” noticed on palpation).

image Tumors: In contrast to hydrocele, tumors do not transluminate.


INFECTIONS



11 What is epididymoorchitis?


Epididymoorchitis is an inflammation of the epididymis and testis. Infections reach the testis and epididymis hematogenously or by an ascending route from the urethra and ductus deferens. The most important pathogens include:


image Sexually transmitted pathogens, such as Neisseria gonorrhoeae, Ureaplasma urealyticum, and Chlamydia trachomatis, are typically found in young adults.

image Uropathogens, such as Escherichia coli, Pseudomonas aeruginosa, and Klebsiella, cause epididymoorchitis in the elderly suffering from prostatic hyperplasia and urinary tract infections.

image Viruses, such as the mumps virus, reach the scrotum testis through the hematogenous route and cause predominantly orchitis in children.


12 What is balanitis?


Balanitis is an inflammation of the glans penis. In men who are not circumcised, it is associated with an inflammation of the foreskin (balanoposthitis). Nonspecific bacterial balanitis is usually a consequence of poor hygiene.



13 What are the common causes of ulceration on the glans penis?



image Genital herpes: Herpes simplex virus 2 (HSV-2) infection presents with vesicles that ulcerate and heal by formation of crusts.

image Syphilis: Treponema pallidum infection may result in the formation of an ulceration (syphilitic chancre).

image Chancroid: Painful ulcer, associated with local swelling and enlargement of inguinal lymph nodes, is caused by Hemophilus ducreyi.


14 How does gonorrhea present clinically?


Infection with N. gonorrhoeae usually causes urethritis presenting with a purulent urethral discharge. If the discharge is examined under the microscope, Neisseriae may be seen as paired cocci (diplococci) in the cytoplasm of neutrophils in the smear.



15 What is Peyronie disease?


Peyronie disease is a fibromatosis of unknown etiology involving the fasciae of the penile shaft. Progressive fibrosis is associated with curvature of the penis and painful erection and intercourse.



NEOPLASMS AND RELATED CONDITIONS



16 What is the most common neoplasm of the male genital tract?


Prostatic carcinoma, a cancer of old age. In men younger than 40 years, testicular tumors are the most common genital cancer.



17 List the most important facts about testicular tumors



image They are uncommon tumors. Incidence is only 5 per 100,000 men.

image They account for less than 1% of all malignant tumors in males.

image Peak incidence in the 30- to 40-year-old age group. They are rare in prepubertal children and the elderly.

image Most tumors (>90%) are of germ cell origin.

image Most tumors (>90%) are malignant.

image Serum tumor markers found in approximately 50% patients. These markers include alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG).

image Platinum-based chemotherapy combined with surgery gives excellent results (>90% cure rate).


18 What are the risk factors for testicular cancer?



image Sex chromosome abnormalities: Germ cell tumors occur at a rate of 25% in dysgenetic gonads, intersexes, hermaphrodites, and pseudohermaphrodites. Fortunately, these conditions are rare.

image Cryptorchidism: This anomaly is associated with a 10-fold increase in the incidence of germ cell tumors. It is not known whether the tumors develop because the testis is in an abnormal location or whether the testis is retained because it is abnormal.


19 Explain the histogenesis of testicular germ cell tumors


Testicular germ cell tumors originate from intratubular germ cells, probably spermatogonia or primordial germ cells, that have undergone malignant transformation. Malignant transformation is accompanied by distinct morphologic changes that can be recognized histologically as carcinoma in situ or intratubular testicular germ cell neoplasia (ITTGCN). Malignant germ cells have enlarged, hyperchromatic nuclei and well-developed cytoplasm filled with glycogen. Such cells remain inside the tubules for variable periods of time and then give rise to invasive tumor cells that spread outside the seminiferous tubules.



Key Points: Neoplasms and Related Conditions



1. Testicular tumors are relatively rare but important because they affect men in their most productive years, between 30 and 40 years of age.
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Jul 23, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on The Male Genital System

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