Chapter 109. Genital Malformations The Male - Review of Medical Embryology Book

Epispadias: seen in 1/30,000 infants where the urethra opens on the dorsal surface of the penis. It often is associated with exstrophy of the bladder. It may involve the glans or the entire penis. It also is seen in the female but is rare and appears as a fissure of the upper urethral wall that opens on the dorsum of the clitoris
Hypospadias seen in 1/300 males where the external urethral opening is on the ventral (under) surface of the penis rather than at the tip of the glans

THE PENIS is often underdeveloped, curves downward (chordee), and we speak of 4 types of hypospadias: glandular, penile, penoscrotal, and perineal
IT ISTHE RESULT of an inadequate production of androgens by the fetal testes, resulting in failure of fusion of the urogenital folds and incomplete formation of the urethra

Cryptorchidism, or undescended testes: seen in about 30% of premature infants and in about 3% of full-term infants. Normal descent into scrotum is complete by first year

IF BOTH TESTES STAY IN or just outside the abdominal cavity, they fail to mature histologically, and sterility is almost certain
THE TESTES MAY BE FOUND in the abdominal cavity or anywhere along the path of testicular descent, but they usually lie in the inguinal canal. May be unilateral or bilateral
CAUSE OF UNDESCENT is unknown, but is probably a failure of normal androgen production

Ectopic testis: rare; in its descent, it deviates from the normal pathway and lodges in abnormal locations, such as the external aponeurosis of the external oblique muscle (interstitial), the thigh (femoral triangle area), dorsal to the penis, or on the opposite side (crossed ectopia)
Hydrocele: abdominal end of the processus vaginalis remains open but is too small for a hernia. Peritoneal fluid passes into processus, and we get a hydrocele of the testis and spermatic cord

IF THE MIDDLE OF THE CANAL OF THE PROCESSUS VAGINALIS stays open, fluid may accumulate and form a hydrocele of the spermatic cord

Congenital inguinal hernia: a persistent processus vaginalis. Loops of intestine may herniate into scrotum or labium majora. More common in males than in females and is associated with cryptorchidism
Agenesis, or absence of penis: failure of the genital tubercle to develop. The urethra opens into the perineum near the anus. Testes and scrotum are normal
V Bifid penis and double penis: failure of fusion of the 2 parts of the genital tubercle results in a bifid condition; formation of 2 tubercles creates a double penis
Micropenis: penis is very small and is hidden by the suprapubic fat. Probably due to a functional hormonal deficiency of the fetal testes. Is commonly associated with hypopituitarism
Retroscrotal penis, or transposition of penis and scrotum: the penis is found behind the scrotum. Due to a failure of the labioscrotal folds to shift caudally as they fuse to form the scrotum. They may even develop in front of the genital tubercle and then fuse