Invasive breast carcinoma - IARC

fers from the prototypical type I
endometrioid adenocarcinoma by its
lack of association with exogenous or
endogenous hyperoestrinism, its lack of
association with endometrial hyperplasia
and its aggressive behaviour {497,
2005,2646}.
Histopathology
S e rous adenocarcinoma is usually, but
not always, characterized by a papillary
a rc h i t e c t u re with the papillae having
b road fibrovascular cores, secondary
and even tert i a ry papillary pro c e s s e s
and prominent sloughing of the cells.
The cells and nuclei are generally ro u n d-
ed rather than columnar and lack a perpendicular
orientation to the basement
membrane. The nuclei are typically
poorly diff e rentiated, are often apically
rather than basally situated and usually
have large, brightly eosinophilic
m a c ronucleoli. Mitoses, often atypical
and bizarre, and multinucleated cells are
commonly present, as are solid cell
nests and foci of necrosis. Psammoma
bodies are found in about 30% of cases
and may be numerous. When the tumour
g rows in a glandular pattern, the glands
a re generally complex and "labyrinthine."
S e rous carcinoma is considered a high
grade carcinoma by definition and is not
graded.
Precursor lesions
A putative precursor of serous adenocarcinoma
is serous endometrial intraepithelial
carcinoma, which has also been
called endometrial carcinoma in situ and
surface serous carcinoma {79,975,2764,
3256}. This lesion is characterized by a
noninvasive replacement of benign (most
commonly atrophic) endometrial surface
and glandular epithelium by highly
malignant cells that resemble those of
invasive serous carcinoma. Sero u s
endometrial intraepithelial carcinoma has
been proposed as the precursor or in situ
phase of serous carcinoma, and in most
reported studies it has co-existed with
invasive serous and, occasionally, clear
cell, adenocarcinoma. Clinically, serous
endometrial intraepithelial carcinoma has
a significance very similar to that of invasive
serous adenocarcinoma since it can
also be associated with disseminated
disease outside the uterus (usually in the
peritoneal cavity) even in the absence of
invasive carcinoma in the endometrium
{79,160,975,2764,3105,3256}.
Fig. 4.09 Serous adenocarcinoma of the endometrium. Broad papillary stalks are covered by secondary
micropapillae with considerable exfoliation of tumour cells.
Prognosis and predictive factors
This tumour has a tendency to develop
deep myometrial invasion and extensive
lymphatic invasion, and patients commonly
present with extrauterine spread at
the time of diagnosis. However, even in
the absence of a large or deeply invasive
tumour extrauterine spread is common,
as are recurrence and a fatal outcome
{160,1370,3105}.
Clear cell adenocarcinoma
Definition
An adenocarcinoma composed mainly of
clear or hobnail cells arranged in solid,
tubulocystic or papillary patterns or a
combination of these patterns.
Fig. 4.10 Surface syncytial change. This benign
papillary syncytial proliferation is distinguished
from serous adenocarcinoma by the lack of atypia.
Epidemiology
The other major type II carcinoma of the
endometrium is clear cell adenocarcinoma.
It is less common than serous carcinoma
(1-5%, as opposed to 5-10% of all
endometrial carcinomas) but occurs in
the same, predominantly older, patient
population.
Tumour spread and staging
Similar to serous adenocarc i n o m a ,
patients with clear cell adenocarcinoma
are frequently diagnosed in advanced
clinical stages.
Histopathology
Histologically, clear, glycogen-filled cells
and hobnail cells that project individually
into lumens and papillary spaces characterize
the typical clear cell adenocarcinoma.
Unlike similarly glycogen-rich
s e c re t o ry endometrioid adenocarc i n o-
mas, clear cell adenocarcinoma contains
large, highly pleomorphic nuclei, often
with bizarre and multinucleated forms.
The architectural growth pattern may be
tubular, papillary, tubulocystic or solid
and most frequently consists of a mixture
of two or more of these pattern s .
Although psammoma bodies are present
in approximately one-third of serous adenocarcinomas,
they are rarely seen in
clear cell adenocarcinomas. Occasiona
l l y, the tumour cells have granular
Epithelial tumours and related lesions 225