CHAPTER 18
Male Reproductive System
361
Figure 18-15A.
Ductuli efferentes.
H&E,
3
68; inset
3
234
There are 15 to 20 tubules of
ductuli efferentes
leading from the
rete testis in the mediastinum to the head of the epididymis. They
are also called
efferent ducts
. The ductuli efferentes are lined by two
types of epithelial cells:
nonciliated cuboidal cells
with
microvilli
(absorptive cells)
and
ciliated columnar cells
. They are alternately
distributed on the luminal surface of the ductuli efferentes. The epi-
thelium of the ductuli efferentes is supported by a thin layer of con-
nective tissue; beneath it is a thin layer of circular smooth muscle
that contracts to move testicular fl
uid and spermatozoa toward the
ductus epididymis (
inset
). Smooth muscle cells are interspersed with
some elastic F
bers. The muscle layer becomes thicker as it nears the
ductus epididymis.
Spermatozoa
Spermatozoa
Spermatozoa
Ductuli
Ductuli
efferentes
efferentes
Ductuli
efferentes
Artery
Artery
Artery
A
Ciliated
Ciliated
columnar cells
columnar cells
Ciliated
columnar cells
Spermatozoa
Spermatozoa
Spermatozoa
Nonciliated
Nonciliated
cuboidal cells
cuboidal cells
Nonciliated
cuboidal cells
B
Figure 18-15B.
Ductuli efferentes.
H&E,
3
463
An example of
ductuli efferentes
at high magniF
cation is shown.
The
nonciliated cuboidal cells
have an absorptive function, absorbing
excess testicular fl uid secreted by seminiferous tubules and increasing
the concentration of spermatozoa in the lumen of the ductuli effer-
entes. The
ciliated columnar cells
of the ductuli efferentes have a
motile function, sweeping spermatozoa and testicular fl
uid toward
the epididymis.
CLINICAL CORRELATION
Figure 18-15C.
Testis Seminoma.
H&E,
3
192
Most tumors of the testes arise from the germinal epithelium of
the seminiferous tubules; therefore, this group is termed
germ cell
tumors
. These germ cell tumors can be divided into
seminomas
, and
all other germ cell tumors are called
nonseminomatous
, examples
of which include
choriocarcinoma
,
embryonal carcinoma
,
yolk sac
tumor
, and
teratoma
. Seminomas are the most common germ cell
tumor of the testis and are most likely to occur in the pure form,
because germ cell tumors commonly contain multiple tumor types
(
mixed germ cell tumors
). Germ cell tumors tend to arise from
in situ
lesions of the germinal epithelium called
intratubular germ cell neo-
plasia (IGCN)
. The incidence of seminoma peaks in the fourth and
F fth decades of life.
Cryptorchidism
and
gonadal dysgenesis
are risk
factors for germ cell tumors. Patients present with painless enlarge-
ment of the testis. Grossly, classic seminomas are circumscribed and
fl eshy. Histologically, classic seminoma consists of sheets of large cells
with distinct cell borders and nucleoli, inF ltrated with
lymphocytes
.
These cells are typically positive for
placental alkaline phosphatase
on immunohistochemical preparations. Because of the potential for
seeding across fascial planes, biopsy is not recommended. Semino-
mas are very sensitive to radiation and chemotherapy.
Lymphocytes
Seminoma
C
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