Invasive breast carcinoma - IARC

A
B
C
Fig. 2.88 Dysgerminoma. A This tumour has thick septa with an extensive chronic inflammatory reaction of granulomatous type. B Aggregates of tumour cells are
separated by fibrous tissue septa infiltrated by lymphocytes. C Occasional beta-human chorionic gonadotropin-positive syncytiotrophoblasts occur. D The tumour
cells show membranous staining for placental-like alkaline phosphatase.
D
ulative necrosis may be present and may
be associated with cystic change or
macroscopic calcification. However, the
presence of minute, sandy calcifications
should point towards the presence of a
concomitant gonadoblastoma. Focal
haemorrhagic areas may be indicative of
the presence of other germ cell components,
possibly containing trophoblastic
tissue.
Histopathology
The proliferating germ cells have a
monotonous appearance with a polygonal
shape, abundant pale cytoplasm and
fairly uniform nuclei. They aggregate in
cords and clumps, although sometimes
the lack of cohesion between cells may
lead to the formation of pseudoglandular
spaces. Although the stroma is usually
reduced to thin perivascular sheaths,
occasionally it can be abundant. It
always contains variable amounts of
c h ronic inflammatory infiltrate, mainly
composed of T lymphocytes {700} and
macrophages. In fact, epithelioid granulomas
are a prominent feature in a quarter
of cases. Inflammation can also be
present in the metastases. The mitotic
rate is variable, and some tumours show
anisokaryosis. Differentiation in the form
of syncytiotrophoblastic cells is found in
5% of cases {3246}. In these cases,
beta-human chorionic gonadotropin (βhCG)-secreting
syncytiotrophoblast originates
directly from dysgerminoma cells
without intervening cytotrophoblast.
Immunoprofile
Most dysgerminomas show positivity for
vimentin and placental-like alkaline
phosphatase (PLAP) {1660,2011}, the
latter is usually found in a membranous
location. An inconstant and heterogeneous
cytoplasmic positivity can be
found to cytoskeletal proteins such as
cytokeratins (rarely), desmin, glial fibrillary
acidic protein, as well as to S-100
protein and carcinoembryonic antigen
(CEA). C-kit gene product (CD117) is
present in dysgerminoma as it is in seminoma
{2965}, further supporting the similarity
to its testicular counterpart.
Precursor lesions
There is no known precursor lesion for
the vast majority of dysgerm i n o m a s ,
except for those arising fro m
gonadoblastoma.
Histogenesis
Some dysgerminomas may subsequently
be the precursors of other primitive
germ cells neoplasms such as yolk sac
tumour {2185}.
Prognosis and predictive factors
Dysgerminomas respond to chemotherapy
or radiotherapy. The clinical stage of
the tumour is probably the only significant
prognostic factor {2605}. The presence
of a high mitotic index and, in some
164 Tumours of the ovary and peritoneum