Abnormalities of male genitalia
Hypospadia is a relatively frequent disorder of the external genitalia (3:1000 births), while epispadia is a very rare anomaly (1:30'000 births) and frequently associated with other complications.
Hypospadia is the most frequent penile abnormality whereby the incidence, depending on which author is consulted, is given as being between 1 - 8 / 1000 newborn boys. A closure disorder of the urethral groove on the underside of the penis is involved.
One distinguishes various anatomic variants:
- Hypospadia of the glans penis is characterized by a urinary meatus on the underside of the glans.
- With a hypospadia of the penile shaft, the urinary meatus is in the middle of the penis.
- In a hypospadia of the scrotum the fusion of the genital swellings is absent and a urethral opening at the level of the scrotum remains.
From an embryologic point of view, hypospadias of the penis and scrotum arise from a closure disorder of the urethral groove (spongy part of the urethra) by the urethral folds or the genital swellings, going out from the urethral plate, which has an endodermal origin. The urethral groove closes in the posterior part through fusion of the genital swellings and anteriorly progressively through the closure of the urethral folds up to the glans. The urethra within the glans has an ectodermal origin. So hypospadia glandis can be traced back to a closure disorder of the epithelial lamella on the penile tip and can extend up to the navicular fossa.
The cause for this disorder is multi-factorial: besides genetic factors the damaging effects of a hormone therapy with progesterone during the first month of pregnancy also plays a role. An altered synthesis of testosterone (or its derivative) and/or an anomaly of the receptors for this hormone can also be blamed.
Under the most frequent abnormalities associated with a hypospadia are penile deviations, a stenosis of the urinary meatus and a deviation of the raphe mediana. Finally, a hypoplasia of the cavernous body, leading to a micropenis, is also not rare.
Hormone therapy (in the case of a micropenis) for stimulating growth is often combined with a surgical reconstruction of the urethra.
Epispadia is a much more rare abnormality than hypospadia and is seen in only 1 / 300'000 newborns. It also occurs in girls (1 girl: 5 boys). Here the urinary meatus is localized on the upper side of the penis or clitoris.
From an embryologic point of view this abnormality can be traced back to a disorder of the mesoderm cell migration during the 4th developmental week. Depending on how strongly affected the person is, an exstrophy of the urinary bladder together with epispadia or only an isolated epispadia results.
Agenesis of the penis / clitoris
Penile or clitoris aplasia is a very rare abnormality. Here the development of the genital tubercle due to an ectoderm-mesenchymal anomaly during the 7th developmental week is involved.
Bifid penis or clitoris / micropenis
This disorder is extremely rare and occurs in both sexes. It is mostly associated with an ecstrophia of the urinary bladder or anomalies in the region of the urinary tract. From an embryologic point of view two genital eminences have been developed.
Cryptorchidism / ectopia of the testicles
Cryptorchidism, a term of Greek origin (κρυπτος = hidden, ορξις = testis), is found in ca. 30% of premature infants and in 4% of full term babies. The testes remain in the abdominal cavity or somewhere on their way to the scrotum – most frequently in the inguinal canal (60% of the cases). One should not confuse the concept of cryptorchidism with a testicular ectopia, in which the testes take on an abnormal location due to a deviant migration. Cryptorchidism can occur unilaterally or bilaterally (20-40% of all cryptorchidisms).
The cause of this disorder remains unknown but it seems to be connected with an insufficient production of androgens (possibly through a change at the level of the hypothalamus-pituitary axis). An undescended testis is normal up till birth, but already during the first year there are histological alterations (frequency of testicular tumors is elevated by 20-40%; there also exists a risk of sterility).
The first treatment step consists in giving gonadotropic hormones (HCG) with a success rate of 20-50% or, if this remains unsuccessful, in a surgical intervention (orchidopexy). Here the testis is surgically brought down into the scrotum.
Inguinal hernia / hydrocele / cysts
Normally, during the first year of life the upper section of the vaginal process closes and only the peritoneo-vaginal ligament remains. Only a small sack on the ventral surface of the testes remains. A double-walled serous structure, the vaginal tunica, is involved.
If the vaginal process is not obliterated, but stays open, intestinal loops can slide into it and cause a congenital inguinal hernia. Such hernias can be more or less extensive, depending on the dehiscence between the visceral peritoneum of the intestinal loops and the vaginal process (parietal peritoneum).
It can also happen that the opening is too small for the intestinal loop and instead peritoneal fluid can collect therein, forming a cyst in the spermatic cord, if the fluid is closed in above the testes or a testicular hydrocele can be formed when a serous discharge collects between the layers of the vaginal tunica.
Torsion of the spermatic cord, mistakenly called a testicular torsion, is connected with a congenital anomaly of the testicular fixation at the lower scrotal pole. Thereby the spermatic cord (deferent duct and testicular blood vessels) can twist around its axis.
Through this, the testicular artery gets compressed and an ischemia (insufficient perfusion of the testis) arises. This is always a urologic emergency. The treatment is always surgical and must take place within the first 6 hours to avoid irreversible damage to the testis. This torsion can appear at any time up to adolescence, but is rarely encountered in adults.