Invasive breast carcinoma - IARC

Immunoprofile
The cases studied by Damiani et al. {616}
showed diffuse and strong immunore a c-
tivity with an anti mitochondrial antibody.
Epithelial membrane antigen outlined the
luminal borders of neoplastic glands
when these were present. GCDFP-15 was
absent in 3 cases and ER was observed
in 90% of the cells in one {616}.
Prognosis and predictive factors
The follow up and number of re p o rt e d
cases is too small to allow meaningful
discussion of prognosis.
Adenoid cystic carcinoma
D e f i n i t i o n
A carcinoma of low aggressive potential,
histologically similar to the salivary gland
c o u n t e r p a rt .
ICD-O code 8 2 0 0 / 3
S y n o n y m s
C a rcinoma adenoides cysticum, adenocystic
basal cell carcinoma, cylindro m a-
tous carc i n o m a .
E p i d e m i o l o g y
Adenoid cystic carcinoma (ACC) re p resent
about 0.1% of breast carc i n o m a s
{149,1581}. It is important that stringent
criteria are adopted to avoid misclassified
lesions as found in about 50% of the
cases re c o rded by the Connecticut
Tumor Registry {2815}. The age distribution,
is similar to that seen in infiltrating
duct carcinomas in general {2419}.
Clinical features
The lesions are equally distributed
between the two breasts and about 50%
a re found in the sub-periareolar re g i o n
{149}. They may be painful or tender and
unexpectedly cystic. A discrete nodule is
the most common pre s e n t a t i o n .
Macroscopy
The size varies from 0.7 to 12 cm, with an
average amongst most re p o rted cases of
3 cm. Tumours are usually circ u m s c r i b e d ,
and microcysts are evident. They are
pink, tan or grey in appearance {2309,
2 4 1 9 } .
H i s t o p a t h o l o g y
ACC of the breast is very similar to that of
the salivary gland, lung and cervix {1838}.
Fig. 1.56 Adenoid cystic carcinoma. The typical
fenestrated nests composed of two cell types (dominant
basaloid and few eosinophilic) are shown.
Fig. 1.57 Adenoid cystic carcioma. In this case,
there is a predominant tubular architecture.
T h ree basic patterns are seen: trabecul
a r- t u b u l a r, cribriform and solid. The 3
p a t t e rns have been used by Ro et al.
{2381} to develop their grading system.
The cribriform pattern is the most characteristic
as the neoplastic areas are
p e rforated by small apert u res like a
sieve. The "apert u res" are of two types:
The first, also re f e r red to as pseudolumens
{1406}, results from intratumoral
invaginations of the stroma (stro m a l
space). Accord i n g l y, this type of space
is of varying shape, mostly round, and
contains myxoid acidic stromal mucosubstances
which stain with Alcian blue
{152} or straps of collagen with small
capillaries. Sometimes the stro m a l
spaces are filled by hyaline collagen
and the smallest are constituted by
small spherules or cylinders of hyaline
material which has been shown ultrastructurally
and immunohistochemically
to be basal lamina {463}. With immunoh
i s t o c h e m i s t ry a rim of laminin and collagen
IV positive material outlines the
s t romal spaces. The second type of
space is more difficult to see as it is less
n u m e rous and usually composed of
small lumina. These are genuine secret
o ry glandular structures (glandular
space) which contain eosinophilic granular
secretion of neutral mucosubstances,
and are periodic acid-Schiff
positive after diastase digestion {152}.
The dual structural pattern reflects a
dual cell component. The basaloid cell
has scanty cytoplasm, a round to ovoid
nucleus and one to two nucleoli {1581}.
It constitutes the bulk of the lesion and
also lines the cribriform stromal spaces.
The second type of cell lines the true
glandular lumina, and has eosinophilic
cytoplasm and round nuclei similar to
those of the basaloid cells. A third type
of cell seen in 14% of cases by
Tavassoli and Norris {2885} consists of
sebaceous elements that can occasionally
be numero u s .
ACC contains a central core of neoplastic
cells, surrounded by areas of invasion;
ductal carcinoma in situ is absent
at the periphery. The stroma varies fro m
tissue very similar to that seen in the
n o rmal breast to desmoplastic, myxoid
or even extensively adipose.
ACC has been seen in association with
adenomyoepithelioma {2994} and low
grade syringomatous (adenosquamous)
c a rcinoma {2419} which suggests a
close relationship among these combined
epithelial and myoepithelial
t u m o u r s .
Differential diagnosis
ACC must be distinguished from benign
collagenous spherulosis {519} and fro m
c r i b r i f o rm carcinoma, which more closely
simulates ACC. Cribriform carc i n o m a
is characterized by proliferation of one
type of neoplastic cell only, and one
type of mucosubstance. In addition,
e s t rogen and pro g e s t e rone re c e p t o r s
a re abundant in cribriform carc i n o m a s
and absent from virtually all cases of
ACC {2381}.
Immunoprofile and ultrastructure
The two main cell types are diff e rent at
both ultrastructural and immunohistochemical
levels.
U l t r a s t r u c t u r a l l y, the basaloid cells have
myoepithelial features particularly when
located at the interstitial surface that
lines the pseudoglandular spaces
{3244}. They show thin cytoplasmic filaments
with points of focal condensation
{3094}. These cells have been shown to
be positive for actomyosin {105} and
similar to myoepithelial cells are posi-
44 Tumours of the breast