Invasive breast carcinoma - IARC

A
B
Fig. 2.112 Mixed germ cell-sex cord-stromal tumour. A The sectioned surface shows a lobulated, pale yellow tumour. B The tumour is composed of an admixture
of smaller sex cord cells and larger germ cells with clear cytoplasm forming cords and trabeculae surrounded by loose oedematous connective tissue. C Small carrot-shaped
sex cord cells are admixed with large pale germ cells in a haphazard fashion. .
C
Histopathological criteria
Pure gonadoblastoma may show extensive
involvement of the gonad but does
not behave as a malignant lesion {2598,
2849,2850}. More frequently, its germ
cell component gives rise to a malignant
germ cell neoplasm capable of invasion
and metastases. Gonadoblastoma may
sometimes undergo ablation by a
process of marked hyalinization and calcification.
In such cases the lesion
becomes innocuous, but great care must
be taken to exclude the presence of
viable elements, especially of germ cell
lineage.
D y s g e rminoma arising within
gonadoblastoma tends to metastasize
less frequently and at a later stage than
dysgerminoma arising de novo {2598,
2849,2850}. There is no satisfactory
explanation for this phenomenon. The
patients can be treated similarly to
patients with pure dysgerminoma with a
very high likelihood of complete cure.
Mixed germ cell-sex cord-stromal
tumour
Definition
A neoplasm composed of intimately
admixed germ cells and sex cord derivatives
that has a different histological
appearance from gonadoblastoma.
Mixed germ cell-sex cord-stromal tumour
also differs from gonadoblastoma by its
occurrence in anatomically, phenotypically
and genetically normal females
{2844,2845,2847}.
Epidemiology
Mixed germ cell-sex cord - s t ro m a l
tumours usually occur in infants or children
under the age of 10, but have been
occasionally reported in postmenarchal
women {1556,2844,2852}.
Aetiology
Patients with mixed germ cell-sex cords
t romal tumour have normal gonadal
development and a normal XX karyotype.
The tumour is not associated with
gonadal dysgenesis, and its aetiology is
unknown {1556,2844,2852,3270}.
Clinical features
Patients with a mixed germ cell-sex cordstromal
tumour generally present with
lower abdominal pain. In almost a fourth
of the cases patients have isosexual
pseudoprecocity and may have vaginal
bleeding and bilateral breast development
{1556,2852,3270}. Physical examination
routinely reveals a large mass in
the adnexal area or in the lower
abdomen.
Macroscopy
This tumour, unlike gonadoblastoma,
tends to be relatively large, measuring
7.5-18 cm and weighing 100-1,050
grams. Except for two reported cases,
mixed germ cell-sex cord-stromal tumour
is unilateral {1321,2849,2850}. The
tumour is usually round or oval and is
surrounded by a smooth, grey or greyyellow
capsule. In most cases it is solid,
but in some cases it may be partly cystic.
The sectioned surface is grey-pink or yellow
to pale brown. There is no evidence
of calcification. In all cases the fallopian
tube, the uterus and the external genitalia
are normal
Tumour spread and staging
Since mixed germ cell-sex cord-stromal
tumours are less aggressive than
gonadoblastoma and uncommonly bilateral,
the routine evaluation of patients
with a mixed germ cell-sex cord-stromal
tumour can be less extensive. Although
the tumours are often of considerable
size, metastases have occurred in only
two cases {124,1556}. If intraoperative
consultation is inconclusive, it is appropriate
to limit the operation to removal of
the involved gonad and to await the final
pathology results before performing any
definitive surgery that might impair future
fertility.
Histopathology
Mixed germ cell-sex cord-stromal tumour
is composed of germ cells and sex cord
derivatives resembling immature Sertoli
or granulosa cells intimately admixed
with each other. The tumour cells form
four distinctive histological patterns as
follows:
(1). A cord-like or trabecular pattern
composed of long, narro w, ramifying
c o rds or trabeculae that in places
expand to form wider columns and larger
round cellular aggregates surrounded
by connective tissue stroma that varies
from dense and hyalinized to loose and
oedematous.
(2). A tubular pattern composed of solid
tubules surrounded by fine connective
tissue septa and containing peripherally
located smaller epithelial-like sex cord
derivatives surrounding large, ro u n d
germ cells with clear or slightly granular
cytoplasm and large vesicular nuclei
containing prominent nucleoli.
(3). A haphazard pattern consisting of
scattered collections of germ cells surrounded
by sex cord derivatives, which
may be very abundant.
(4). A mixed pattern showing an admixture
of the three above mentioned patterns
without any predominance.
The germ cells show mitotic activity and
a close similarity to those of dysgerminoma,
but in some cases they are better differentiated
showing smaller nuclei and
less marked mitotic activity. Unlike the
178 Tumours of the ovary and peritoneum