Invasive breast carcinoma - IARC

Fig. 1.39 Apocrine carcinoma. Note abundant
eosinophilic cytoplasm and vesicular nuclei.
Fig. 1.40 Apocrine carcinoma, surperficially resembling
a granular cell tumour.
Fig. 1.41 Apocrine carcinoma. Immunostaining shows
intense positivity for GCDFP-15.
to as myoblastomatoid {806}. Type B
cell shows abundant cytoplasm in which
fine empty vacuoles are seen. These latter
result in foamy appearance so that
the cells may resemble histiocytes and
sebaceous cells. Nuclei are similar to
those in type A cells. These same cells
have been designated as sebocrine
{2876}. (See also Sebaceous carc i n o-
ma, page 46). C a rcinomas composed
p u rely of foamy apocrine cells may
s u r p e rfically resemble a histiocytic proliferation
or even an inflammatory re a c-
tion {806}. In difficult cases, both granular
cell tumours and histiocytic pro l i f e r a-
tions can be easily distinguished by
staining the tumours with keratin antibodies
that are positive only in apocrine
c a rc i n o m a s .
Immunoprofile
Apocrine carcinomas are typically
GCDFP-15 positive and BCL2 pro t e i n
negative. Expression of GCDFP-15 is a
f e a t u re common to many variants of
b reast carcinoma, however, and has
been used to support breast origin in
metastatic carcinomas of unknown prim
a ry site. Estrogen and pro g e s t e ro n e
receptors are usually negative in apocrine
carcinoma by immonuhistochemical
assessment. Interestingly, many ER-,
PR- apocrine carcinomas do have the
ERmRNA, but fail to produce the pro t e i n
{336}. The expression of other biological
markers is in general similar to that
of other carcinomas {177,1605,2425}.
A n d rogen receptors have been re p o rted
as positive in 97% of ADCIS in one
series {1605} and 81% in another
{2624}. Sixty-two percent of invasive
duct carcinomas were positive in the
latter series {2624} and in 22% of cases
in another study {1874}. The significance
of AR in apocrine carcinomas is
u n c e rt a i n .
G e n e t i c s
Molecular studies in benign, hyperplastic
and neoplastic apocrine lesions parallel
those seen in non apocrine
tumours {1357,1673}.
Prognosis and predictive factors
Survival analysis of 72 cases of invasive
apocrine duct carcinoma compared with
non apocrine duct carcinoma re v e a l e d
no statistical diff e rence {17,809}.
Metaplastic carcinomas
D e f i n i t i o n
Metaplastic carcinoma is a general
t e rm referring to a hetero g e n e o u s
g roup of neoplasms generally characterized
by an intimate admixture of aden
o c a rcinoma with dominant areas of
spindle cell, squamous, and/or mesenchymal
diff e rentiation; the metaplastic
spindle cell and squamous cell carcinomas
may present in a pure form
without any admixture with a re c o g n i z a-
ble adenocarcinoma. Metaplastic carc i-
nomas can be classified into bro a d
subtypes according to the phenotypic
appearance of the tumour.
ICD-O code 8 5 7 5 / 3
S y n o n y m s
Matrix producing carcinoma, carc i n o-
s a rcoma, spindle cell carc i n o m a .
E p i d e m i o l o g y
Metaplastic carcinomas account for
less than 1% of all invasive mammary
c a rcinomas {1273}. The average age at
p resentation is 55.
Clinical features
Clinical presentation is not diff e rent fro m
that of infiltrating duct NOS carc i n o m a .
Most patients present with a well circ u m-
scribed palpable mass, with a median
size of 3-4 cm, in some re p o rts more
than half of these tumours measure over
5 cm, with some massive lesions (>20
cm) which may displace the nipple and
ulcerate through the skin.
On mammography, most metaplastic
c a rcinomas appear as well delineated
mass densities. Microcalcifications are
not a common feature, but may be pre s-
ent in the adenocarcinomatous are a s ;
ossification, when present, is, of course,
a p p a rent on mammography.
Macroscopy
The tumours are firm, well delineated
and often solid on cut surface. Squamous
or chondroid diff e rentiation is
reflected as pearly white to firm glistening
areas on the cut surface. One large
and/or multiple small cysts may be
a p p a rent on the cut surface of larger
squamous tumours.
Table 1.08
Classification of metaplastic carcinomas.
Purely epithelial
Squamous
Large cell keratinizing
Spindle cell
Acantholytic
Adenocarcinoma with spindle cell differentiation
Adenosquamous, including mucoepidermoid
Mixed epithelial and Mesenchymal
(specify components)
Carcinoma with chondroid metaplasia
Carcinoma with osseous metaplasia
Carcinosarcoma (specify components)
Invasive breast cancer
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