Invasive breast carcinoma - IARC

A
Fig. 2.10 Invasive peritoneal implant of the omentum. A Adipose tissue is invaded by haphazardly distributed
glands and small cell clusters accompanied by a dense fibrous stromal reaction. B Haphazardly distributed glands
and small cell clusters exhibit marked nuclear atypia and are accompanied by a dense fibrous stromal reaction.
B
Fig. 2.11 Serous borderline tumour. A lymph node
contains epithelial inclusions of serous borderline
tumour showing the typical papillary growth pattern.
10 year survival rates, the invasive form
is associated with a poor prognosis, i.e.
more than 50% have recurrences, and
the 10 year survival rate is only about
35%. Therefore, the morphology of the
peritoneal implants is the main prognostic
factor for patients with stage II-III SBT.
When underlying tissue is absent in a
biopsy specimen, the lesion is classified
as non-invasive on the assumption that it
has been stripped away with ease
{2605}. It is important to note that
implants are heterogeneous, and various
types may coexist in diff e rent are a s ;
therefore, sampling of as many implants
as feasible is recommended. The omentum
is the most likely site for invasive
implants. Therefore, surgeons must take
a sufficient amount of omental tissue to
enable the pathologist to distinguish noninvasive
from invasive implants. In turn,
the pathologist must assess multiple
samples of macroscopically "norm a l "
appearing omentum to ascertain adequate
sampling.
Invasive implants should be distinguished
from benign epithelial inclusions
and foci of endosalpingiosis. The latter
are uncommon, occurring between a fifth
and a tenth as often as implants {207}.
Benign epithelial inclusions are characterized
by small, generally round glands
lined by a single layer of flat to low
columnar cells without atypia or mitotic
activity, often associated with a fibrous
stroma. Small rounded glands also characterize
endosalpingiosis, but the latter
may be papillary and the lining cells
show the typical appearance of tubal
epithelium (ciliated, secretory and intercalated
cells).
Lymph node involvement
Pelvic and para-aortic lymph nodes are
involved by SBT in about 20% of cases;
this finding appears to be without clinical
significance. These lesions may be true
metastases in peripheral sinuses, mesothelial
cells in sinuses misinterpreted as
tumour cells or independent primary
SBTs arising in müllerian inclusion glands
that are present in 25-30% of pelvic and
para-aortic lymph nodes.
Somatic genetics
The pattern of genetic alterations
described in SBTs (for review see {1159})
differs from that of invasive carcinomas,
e.g. TP53 mutations are most often absent
in typical {838,1408} and micropapillary
SBTs {1408}, but are present in up
to 88% of cases of invasive serous carcinoma.
Loss of heterozygosity on the long
arm of the inactivated X chromosome
{464} is characteristic for SBT and rare in
c a rcinomas (for review see {838}).
C h romosomal imbalances have been
identified in 3 of 9 SBTs, 4 of 10
micropapillary SBTs and 9 of 11 serous
c a rcinomas by comparative genomic
hybridization; some changes in micropapillary
SBT are shared with SBT and
others with serous carcinomas only suggesting
a relationship among them
{2771}. The genetic profile indicates that
SBTs are a separate category with little
capacity to transform into a malignant
phenotype. The situation concern i n g
micropapillary SBTs has to be clarified.
Prognosis and predictive factors
Clinical criteria
Stage 1 SBTs do not pro g ress and have
an indolent clinical course with a 5-year
survival rate of up to 99% {1542} and a
10-year survival which is not much worse.
In stage III SBTs, i.e. distributed thro u g h-
out the abdominal cavity with peritoneal
implants (for details see below), the
5-year survival rate ranges between
55-75%, and the probability of a 10-year
survival is not significantly worse.
Histopathological criteria
Compared to typical SBTs, it has been
suggested that micropapillary SBTs have
a higher frequency of bilaterality (59-71%
vs. 25-30%) {754,2727}, an increased risk
of re c u r rence among higher stage lesions
{ 2 7 2 7 }, m o re frequent ovarian surf a c e
involvement (50-65% vs. 36%) and pro b a-
bly a higher frequency of advanced stage
at presentation (48-66% vs. 32-35%) at
least among referral cases {376,754}.
Several re p o rts based on large series of
cases, however, have demonstrated no
d i ff e rence in survival among patients with
typical SBT and those with a micro p a p i l-
l a ry pattern among specific stages {658,
754,1000,1412,2285,2727}, indicating a
need for further investigation of the significance
of the micro p a p i l l a ry pattern. In
addition to its indolent course, micro p a p-
i l l a ry SBT differs from conventional sero u s
c a rcinoma by its lack of re s p o n s i v e n e s s
to platinum-based chemotherapy {210}.
Cytophotometric predictive factors
The most reliable approach is the application
of DNA-cytophotometry (preferably
the static variant) according to the
guidelines of the 1997 ESACP consensus
report {1011,1141}. About 95% of
SBTs display a diploid DNA-histogram
with only a few cells in the 4c region indicating
their low proliferative activity and
only minor genetic alterations associated
with an excellent clinical outcome {1380}.
On the other hand, aneuploid SBTs characterized
by a stemline deviation have a
high recurrence rate, and the patients
die frequently of their disease.
For peritoneal implants DNA-cytophotometry
is also of prognostic importance
because aneuploid implants were found
Surface epithelial-stromal tumours 123