Abormal Development of the Penis and Male Urethra
David A. Hatch, M.D.

If the fusion of the urethral folds fail to progress distally on the ventral penis, the urethra will be shortened. Hypospadias occurs when the fusion of the urethral folds stops proximal to the tip of the glans penis. The term, hypospadias, means under [hypo] the rent [spadon]. The rent refers to the appearance of the ventral glans penis. It appears to have been ripped (rent) apart. Hypospadias can occur anywhere along the urethral groove. In mild forms, the urethra opens just under the corona glandis. This is called coronal hypospadias.
When the internal urethral folds fail to fuse, causing hypospadias, the external urethral folds usually fail to fuse, causing a dorsal hood foreskin. Notice that the median raphé lies at an angle on the penile shaft.
Occasionally, the urethra develops only to the junction of the penis and scrotum. This boy has peno-scrotal hypospadias. As in this case, severe forms of hypospadias are accompanied by shortening of the urethral groove that causes ventral tethering of the penis. This condition, called chordee, can be severe enough to make sexual function impossible.

Whenever the foreskin appears shortened or abnormal on the ventral surface of the penis, one should suspect hypospadias. Occasionally, the external urethral folds develop and fuse despite failure of fusion of the internal urethral folds. In these boys, distal hypospadias occurs despite the presence of a complete prepuce. The urethral meatus must be examined before any circumcision is performed to make sure the boy does not have hypospadias.

Hypospadias occurs in about 1/125 infant males. In most cases, the cause of the hypospadias is not known. Certain conditions, however, are known to result in hypospadias. If the testes fail to produce adequate amounts of testosterone, virilization (enlargement and development of the genital tubercle and scrotal swellings) will not be complete and hypospadias will result. Similarly, if the cells of the genital structures lack adequate androgen receptors, hypospadias will occur. If those cells lack the androgen converting enzyme, 5 alpha reductase, inadequate androgen stimulation will follow and hypospadias will occur.

When severe forms of virilization failure occur (perineal hypospadias, or penoscrotal hypospadias with at least one undescended testicle) the infant must be evaluated for intersex (ambiguous genitalia). Intersex can be caused by hormonal abnormalities (congenital adrenal hyperplasia, ect.) and also by abnormal chromosomes (hermaphroditism, etc.).

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©David A. Hatch, M.D., 1996