Introduction
An undescended testicle (also called maldescensus testis, testicular dystopia), describes a testicle not located in the scrotum. This maldevelopment is usually caused by hormonal abnormalities during the embryonic phase. Such an undescended testicle can result in an increased risk of testicular tumors and infertility.
Directly after birth, approx. 3-6% of newborn boys are affected by undescended testicles. Since this malposition can recede spontaneously, only about 0.8 to 1.8% of the boys are affected at the end of the first year of life. Since the testicles descend during embryonic development and migrate into the scrotum, undescended testicles are much more common in premature babies than in those born at maturity and have no disease value until the end of the corrected first year of life.
Cause
Studies have shown that atrophy of Leydig cells (testosterone producing) and the concentration of gonadotropins play an important role in the developmental phase of testicular descent. At the age of 2-3 months, there is usually an increase in gonadotropins and testosterone. This causes a transformation in the testes from gonocytes to the adult dark spermatogonia (adult stem cell pool). Atrophy of these cells leads to a reduced testosterone production and thus to a shifted hormone level. Thus, undescended testicles represent an endocrinopathy and can be treated by administration of appropriate hormones.
Forms of misalignment
The undescended testicle can be divided into different forms, depending on the position of the testicle.
- Testicular retention as a form of undescended testicle : This is the typical “maldescensus testis”. The testis remains in the inguinal canal during descent (28th to 32nd week of embryonic development) into the scrotum.
- Testicular ectopy as a form of undescended testicle: In this case the testis does not take the path given by the gubernaculum testis during descent.
Thus the testis cannot reach the scrotum, but remains in a different place.
- Pendulum testis as a form of undescended testicle: The pendulum testis is a testicle that has actually migrated normally into the scrotum. However, it can temporarily assume a very high position or even an inguinal position in case of strong external stimuli and a vivid cremasteric reflex.
- Sliding testis as a form of undescended testicle: The sliding testis is usually palpated in the region of the groin. It can be moved manually into the scrotum, i.e. the actual path for the testicle is free. However, after “letting go” it immediately slides out of the scrotum into the groin position and therefore requires therapy.
