CRYPTORCHIDISM
Undescended testis (see also Plate 3-5) is the most common genital
anomaly in males, observed in 3% to 4% of U.S. boys at birth. Although most
testis descent occurs prenatally, about 50% of undescended testes at birth
subsequently descend during the first year of life. This condition may be an
isolated birth defect (see Plate 3-5) due to failure of abdominal or
inguinoscrotal testis descent, or it may be associated with conditions such as
androgen insensitivity, Kallmann syndrome, spina bifida, Down syndrome, or
endocrine disruption. Mechanical causes relate to adhesions, anatomic
maldevelopments of the inguinal canal such as hernia uteri inguinalis,
abnormalities of the inguinal ring, the mesorchium, the testis vascular supply,
or gubernaculum. An actual congenital inguinal hernia is present in almost
every case of true undescended testis, with the hernia sac below the testis in
the scrotum. This leads to higher complications such as hydrocele formation and
torsion in affected boys. Undescended testes are also at higher risk of
malignant degeneration; this risk is related to the original location of the
cryptorchid testis and is estimated to occur in 1 of 20 intraabdominal testes
and 1 of 80 inguinal testes. Finally, it is also clear that both unilaterally
and bilaterally cryptorchid men have higher rates of infertility (defined by
paternity rates) compared to men with bilaterally descended testes.
In many prepubertal boys a
condition termed “retractile testis” or pseudocryptorchidism can be confused
with cryptorchidism. Unlike with true undescended testes, retractile testes can
be pulled into the scrotum and will remain there for a finite period of time
before drawing upward again. Retractile testes usually descend into normal
position before or during puberty. It is controversial whether this condition
harbors the same risks as truly cryptorchid testes in terms of infertility and
malignant degeneration. In cases of obesity, the testes may be hidden under the
mons pubic fat and this can also be confused with cryptorchidism. A gentle
examination, helped with moist heat, usually provides enough relaxation to
permit manipulation of the testis into the scrotum. The cooling associated with
undressing for an examination may prompt a cremaster reflex that elevates the
scrotum superiorly.
The longer a testis remains
undescended, the higher the risk of later malignant degeneration, testis
hormonal failure, and infertility. In general, testes that undergo orchiopexy
before puberty are less likely to become cancerous later in life compared to
those that are repaired after puberty. Whether early orchidopexy reduces later
infertility is unproven. Biopsies of crypt- orchid testes at the time of
postpubertal orchiopexy typically reveal tubular atrophy, germ cell aplasia
(Sertoli cells only), and Leydig cell hyperplasia on histology. The time or
critical age after which permanent damage occurs to the undescended testis is
unknown. Degeneration within undescended testes is believed to begin as early
as 5 to 6 years of age and adults with childhood orchidopexy can show
degenerating semen quality and progressive infertility with time. The optimum
time for orchidopexy therapy, therefore, is unclear, but most clinicians
recommend treatment before 1 year of age in a healthy infant.
Treatment for cryptorchidism
includes watchful waiting, hormonal induction, or surgical repair. As a
first-line treatment, clinicians may often try a short course of intramuscular human chorionic gonadotropin (hCG) to raise
testosterone levels and encourage testis descent in inguinal cryptorchidism.
hCG may be effective when cryptorchidism is due to hypopituitarism, but in most
cases it likely stimulates descent of a testis that would otherwise normally
descend. For definitive therapy, one-or two-stage orchidopexy procedures are
performed to reduce the subsequent risk of torsion or inguinal hernia, to bring
the at-risk testis into
the scrotum for palpability
of malignancy and for cosmesis.
Ectopic testis is a testis
that descends but in a pathway that deviates from the usual scrotal end point.
The most common landing sites for ectopic testes are (1) interstitial, on the
oblique muscle; (2) pubopenile; (3) within the femoral triangle; and (4)
perineal. Surgical replacement into the scrotum is indicated for proper testis function and to reduce pain or other
complications.
