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U N I T 1 1
Genitourinary and Reproductive Function
lesions arising on the prepuce or glans as a result of
HPV infection (see Chapter 41).
Most penile cancers are of squamous epithelial cell ori-
gin and include carcinoma in situ, which is restricted to
the epithelium and does not infiltrate the underlying der-
mis, and invasive carcinomas.
14–16
In situ carcinomas of
the penis are include
Bowen disease
and
erythroplasia of
Queyrat
.
15
Bowen disease appears as a sharply demarcated,
erythematous or grayish-white plaque on the shaft of the
penis. Erythroplasia of Queyrat manifests as single or mul-
tiple shiny red, sometimes velvety plaques on the glans or
foreskin. In approximately 10% of men, these lesions may
transform into infiltrating squamous cell cancer.
14,15
Invasive squamous cell carcinoma
of the penis usually
begins as a small lump or ulcer on the glans or inner sur-
face of the prepuce. The lesions are usually slow growing
and have often been present for a year or more before
being brought to medical attention. The lesions are usu-
ally nonpainful until they undergo secondary ulceration
and infection.
14–16,22
If phimosis is present, there may be
painful swelling, purulent drainage, or difficulty urinat-
ing. Metastasis to the inguinal lymph node is character-
istic of early-stage disease, but widespread dissemination
is uncommon until the lesion is far advanced.
Diagnosis usually is based on physical examination
and biopsy results. Computed tomography scans, penile
ultrasonographic studies, and magnetic resonance imaging
(MRI) may be used in the diagnostic workup. Treatment
options vary according to stage, size, location, and inva-
siveness of the tumor. Carcinoma in situ may be treated
conservatively with fluorouracil cream application or laser
treatment.
22
Conservative treatment requires frequent
follow-up examinations. Surgery remains the mainstay of
treatment for invasive carcinoma.
Disorders of the Scrotum andTestes
The testes, or male gonads, are two egg-shaped struc-
tures located outside the abdominal cavity in the scro-
tum. Embryologically, they develop in the abdominal
cavity and then descend through the inguinal canal into
a pouch of peritoneum (which becomes the tunica vagi-
nalis) in the scrotum during the seventh to ninth months
of fetal life.
23
As they descend, the testes pull their arter-
ies, veins, lymphatics, nerves, and conducting excretory
ducts with them. These structures are encased by the
cremaster muscle and layers of fascia that constitute the
spermatic cord (Fig. 39-8A). The descent of the testes is
thought to be mediated by testosterone, which is active
during this stage of fetal development.
After descent of the testes, the inguinal canal closes
almost completely. Failure of this canal to close pre-
disposes to the development of an inguinal hernia later
in life (Fig. 39-8B). An inguinal hernia or “rupture”
is a protrusion of the parietal peritoneum and part of
the intestine through an abnormal opening from the
abdominal cavity. A loop of small bowel may become
incarcerated in an inguinal hernia (strangulated her-
nia), in which case the lumen of the bowel may become
obstructed and its vascular supply compromised.
The testes and epididymis are completely surrounded
by the tunica vaginalis, a serous pouch derived from the
peritoneum during fetal descent of the testes into the
scrotum. The tunica vaginalis has an outer parietal layer
and a deeper visceral layer that adheres to the dense
fibrous covering of the testes, the tunica albuginea. The
tunica albuginea protects the testes and gives them their
ovoid shape. A space exists between these two layers
that typically contains a few milliliters of clear fluid. The
cremaster muscles, which are bands of skeletal muscle
arising from the internal oblique muscles of the trunk,
elevate the testes. The testes receive their arterial blood
supply from the long testicular arteries, which branch
from the aorta. The testicular veins, which drain the
testes, arise from a venous network called the
pampi-
niform plexus
that surrounds the spermatic artery. The
testes are innervated by fibers from both divisions of the
autonomic nervous system. Associated sensory nerves
Spermatic cord
Ductus deferens
Scrotum
Skin
Dartos muscle
and fascia
Layers of
tunica
vaginalis Parietal
Visceral
Testis
Loop of intestine
Skin
Peritoneum
Testis
Testicular vessels
A
B
FIGURE 39-8.
(A)
Anterior view of the spermatic cord and
inguinal canal and coverings of the spermatic cord and testes.
(B)
Indirect inguinal hernia. (Adapted from Moore KL, Agur
AM. Essentials of Clinical Anatomy. 2nd ed. Philadelphia, PA:
Lippincott Williams &Wilkins; 2002:130, 138.)
