Invasive breast carcinoma - IARC
Invasive breast carcinoma - IARC
Invasive breast carcinoma - IARC
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Fig. 1.48 Mucoepidermoid <strong>carcinoma</strong>.This low<br />
grade invasive <strong>carcinoma</strong> is morphologically similar<br />
to its counterpart in the salivary glands.<br />
cy of ductal <strong>carcinoma</strong> in situ in association<br />
with adenosquamous <strong>carcinoma</strong>s is<br />
variable. These tumours lack estrogen<br />
receptor expression {672,3142}.<br />
Prognosis and predictive factors<br />
The majority of case have an excellent<br />
p rognosis, but a pro p o rtion of cases can<br />
behave in a locally aggressive manner<br />
{2995}, re c u r rence appears to be re l a t e d<br />
to adequacy of local excision. Ly m p h<br />
node metastatic spread is extremely rare<br />
and noted in a single case that was<br />
3.5 cm {2995}.<br />
Mixed epithelial / mesenchymal<br />
metaplastic <strong>carcinoma</strong>s<br />
ICD-O code 8575/3<br />
Synonyms<br />
C a rcinoma with osseous metaplasia<br />
(8571/3), <strong>carcinoma</strong> with chondro i d<br />
metaplasia (8571/3), matrix producing<br />
<strong>carcinoma</strong>, carcinosarcoma (8980/3).<br />
Histopathology<br />
This wide variety of tumours, some of<br />
which are also re g a rded as "matrix producing<br />
<strong>carcinoma</strong>s" {1414,2953}, show<br />
infiltrating <strong>carcinoma</strong> mixed with often<br />
h e t e rologous mesenchymal elements<br />
ranging from areas of bland chondro i d<br />
and osseous diff e rentiation to frank<br />
s a rcoma (chondro s a rcoma, osteosarcoma,<br />
rhabdomyosarcoma, liposarc o-<br />
ma, fibro s a rcoma). When the mesenchymal<br />
component is malignant, the<br />
designation of carc i n o s a rcoma is used.<br />
U n d i ff e rentiated spindle cell elements<br />
may form part of the tumour. Grading is<br />
based mainly on nuclear features and,<br />
to a lesser degree, cytoplasmic diff e r-<br />
e n t i a t i o n .<br />
Immunoprofile<br />
The spindle cell elements may show positive<br />
reactivity for cytokeratins, albeit<br />
focally. Chondroid elements are frequently<br />
S-100 positive and may coexpress<br />
cytokeratins, but are negative for actin.<br />
Many of these tumours are negative for<br />
ER and PR both in the adeno<strong>carcinoma</strong><br />
and the mesenchymal areas, but the<br />
adeno<strong>carcinoma</strong> component may be ER<br />
and PR positive if well to moderately diff<br />
e rentiated. In carc i n o s a rcomas, the<br />
mesenchymal component fails to<br />
immunoreact with any epithelial marker.<br />
Differential diagnosis<br />
The differential diagnosis varies for the<br />
different subtypes of metaplastic <strong>carcinoma</strong>.<br />
Angiosarcoma may be confused with the<br />
acantholytic variant of squamous cell<br />
<strong>carcinoma</strong>, but focal areas of squamous<br />
differentiation can be found when sampled<br />
thoroughly. A negative immunoreaction<br />
with vascular endothelial markers<br />
and a positive reaction with cytokeratins<br />
will support the diagnosis of an epithelial<br />
neoplasm.<br />
Fibromatosis and a variety of spindled<br />
mesenchymal tumours may be confused<br />
with spindle cell squamous <strong>carcinoma</strong>;<br />
these are all generally negative for<br />
epithelial markers.<br />
Myoepithelial <strong>carcinoma</strong> is the most difficult<br />
lesion to distinguish from spindle cell<br />
squamous <strong>carcinoma</strong>. The former often<br />
has ducts with prominent to hyperplastic<br />
myoepithelial cells at its periphery, while<br />
the latter may have clear cut focal squamous<br />
differentiation. Reactions to a variety<br />
of immunostains may be similar, with<br />
the possible exception of those myoepithelial<br />
<strong>carcinoma</strong>s that are diffusely<br />
S-100 positive. Electron microscopy may<br />
be needed to distinguish some of these<br />
lesions. Squamous <strong>carcinoma</strong> cells have<br />
abundant tonofilaments and well developed<br />
desmosomes whether spindled or<br />
polygonal. Intercellular bridges are<br />
abundant in the well differentiated areas<br />
In contrast, the spindle cell myoepithelial<br />
<strong>carcinoma</strong>s often have pinocytotic vesicles,<br />
myofibrils and basal lamina in addition<br />
to tonofilaments and desmosomes.<br />
A<br />
B<br />
Fig. 1.49 A Metaplastic <strong>carcinoma</strong> with chondroid differentiation, 77 year old patient, mastectomy. B Carcinoma with mesenchymal (benign osseous and chondroid)<br />
differentiation. Typically, these <strong>carcinoma</strong>s have a well delineated pushing margin. Areas of osseous and/or chondroid differentiation are variably scattered in an<br />
otherwise typical infiltrating ductal <strong>carcinoma</strong>. C Carcinoma with mesenchymal (benign osseous and chondroid) differentiation. The adeno<strong>carcinoma</strong> is admixed,<br />
in part, with chondroid matrix containing lacunar spaces and rare chondrocytes.<br />
C<br />
40 Tumours of the <strong>breast</strong>