Chapter 16 The Male Genital System
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”).
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.
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.
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.
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.
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:
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:
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.
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.
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.