Invasive breast carcinoma - IARC

Germ cell tumours
F. Nogales
A. Talerman
R.A. Kubik-Huch
F.A. Tavassoli
M. Devouassoux-Shisheboran
Definition
A heterogeneous group of tumours
reflecting the capacity for multiple lines
of differentiation of the main stem cell
system. The great majority of these neoplasms
originate at different stages of
development from germ cells that colonize
the ovary.
Epidemiology
Germ cell tumours account for approximately
30% of primary ovarian tumours,
95% of which are mature cystic teratomas
{1409,1502}. The re m a i n i n g
germ cell tumours are malignant and
represent approximately 3% of all ovarian
cancers in We s t e rn countries but
have been reported to represent up to
20% of ovarian tumours in Japanese
women {1970}. The median age at presentation
is 18 years {883}.
Malignant germ cell tumours are the
most common ovarian cancer among
c h i l d ren and adolescent females.
Approximately 60% of ovarian tumours
occurring in women under the age of 21
are of germ cell type, and up to one-third
of them may be malignant {1555}.
Aetiology
The aetiology of ovarian germ cell malignancies
is unknown.
Clinical features
Signs and symptoms
Pain and a mass are the common presentations
in young women {2586,
2587,2903}. Teenagers who present with
abdominal masses and who have never
menstruated should be evaluated for the
possibility of a gonadoblastoma that has
undergone malignant pro g re s s i o n .
Preoperative karyotyping of such individuals
can be helpful to identify underlying
chromosomal abnormalities in cases of
gonadoblastoma.
Imaging
The ultrasonographic appearance of
dermoid cyst ranges from a predominantly
solid-appearing mass due to the
echogenic aspect of sebaceous material
intermixed with hair to a predominantly
cystic mass {2132}. Computed tomography
can accurately diagnose a teratoma
because of fat attenuation within the cyst,
and its complex appearance with dividing
septa, hypodensity, calcified struct
u res, and the identification of the
Rokitansky protuberance {1080,2132}.
Radiographic studies of fetiform teratoma
demonstrate portions of skull, vertebra
and limb bones within the tumour
{19}. There are no diagnostic findings for
other germ tumours; they often have
solid and cystic components.
Histopathology
M o r p h o l o g i c a l l y, the diff e rent tumour
types present in this group replicate in a
distorted, grotesque form various stages
of embryonal development from early,
transient structures to mature adult tissues
that in their turn may also be capable
of undergoing malignant change
{2248}.
Histogenesis
As for histogenesis, they are believed to
be from the primordial germ cells that
migrate into the gonadal ridge at 6 weeks
of embryonic life {2848}. A small proportion
may also arise from non-germ stem
cells present in the adult female genital
tract {2039}.
Primitive germ cell tumours
Definition
Tumours that contain malignant germ cell
elements other than teratoma.
ICD-O codes
Dysgerminoma 9060/3
Yolk sac tumour 9071/3
Embryonal carcinoma 9070/3
Polyembryoma 9072/3
Non-gestational choriocarc i n o m a 9100/3
Mixed germ cell tumour 9085/3
Dysgerminoma
Definition
A tumour composed of a monotonous
proliferation of primitive germ cells associated
with connective tissue septa containing
varying amount of lymphocytes
and macrophages. Occasionally, syncytiotrophoblastic
differentiation or somatic
cysts occur. This tumour is identical to
testicular seminoma.
A
Fig. 2.87 Dysgerminoma in a 28 year old nulligravida woman. A Magnetic resonance image sagital view
shows a 10 x 15 cm predominantly solid tumour with some central cystic changes. B Sectioned surface of
the tumour shows a predominantly solid, multilobulated appearance with some cystic degeneration and foci
of necrosis.
B
Macroscopy
The usually well encapsulated tumour
masses are apparently unilateral in 90%
of cases. Macroscopic involvement of
the contralateral ovary is apparent in
10% of cases, and in another 10% occult
foci of dysgerminoma can be detected
by biopsy {1929}. Tumours average 15
cm in maximal dimension and on section
are solid, uniform or lobular and creamy
white or light tan. Irregular areas of coag-
Germ cell tumours
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