TUMORES RAROS DE LA MAMA

1. METAPLASTIC CARCINOMA OF THE BREAST (CMM)
Education Exhibits
TABLE OF
CONTENTS/
OUTLINE
EPIDEMIOLOGY
CLINICAL
FEATURES
IMAGING
FINDINGS
IMAGEN
PRESENTATIO
N OF CASES
Rare neoplasm (very low prevalence 0.2- 5%)
that resembles a high-grade histological
carcinoma, presents a high incidence of
recurrences, poor prognosis, difficulties at the
time of diagnosis, the establishment of
therapeutic guidelines, and controversy
regarding its nomenclature.
WHO
CLASSIFICATION
CMM
PURE
EPITHELIAL
TYPE
(squamous cell
carcinoma,
spindle cell
carcinoma,
adenosquamous
carcinoma)
MIXED TYPE
(carcinoma with
bone metaplasia,
carcinoma with
chondroid
metaplasia,
matrix-producing
carcinoma and
carcinosarcoma
RARE TUMORS OF THE BREAST:

2. TEACHING POINTS:
Heterogeneous group of tumors characterized by the
coexistence of adenocarcinoma with areas of differentiation
towards other cell lines, non-glandular epithelial or
mesenchymal, in a variable proportion.
When the metaplastic component encompasses a significant
proportion within the tumor, it is then termed metaplastic
carcinoma.
CLINICAL FEATURES
Age of 55-60 years
Radiotherapy
Trauma
Tamoxifen
Lymphedema
secondary to
previous surgery
RISK FACTORS
Clinically presents as a palpable mass
with no predilection for any quadrant
and with rapid growth.
Axillary lymph node involvement
is rare (6 to 40%).
Incidence of metastatic
disease between 5-30%.
Size
(above 5
cm the
prognosis
worsens.
Age
Lymph node
involvement
Metastases
at
presentation
Prognosis: survival is low (<50% at 5 years)

3. MAMMOGRAPHY
Microlobulated or circumscribed tumor in a dense,
heterogeneous or predominantly fatty breast
pattern.
There is usually no association with
microcalcifications or distortion of the breast
architecture.
Large solid masses, complex internal echogenicity or with
presence of hypoechoic and/or cystic areas, being related
to necrosis and cystic degeneration, edges microlobulated
and the margins well circumscribed; almost present
posterior acoustic enhancement; lesions containing
sarcomatous elements tend to create acoustic shadows.
ULTRASOUND
The definitive diagnosis is
always anatomopathological
Depending on its
mesenchymal component,
several subtypes of
metaplastic carcinoma can
be differentiated:
sarcomatous, fibromatous,
and angiosarcoma.
The most common form of
presentation is as squamous
cell carcinoma.

4. Rare tumor of controversial
histogenesis, aggressive behavior
and unusual metastatic pattern to
the gastrointestinal tract and serous
surfaces
Atypical morphological
characteristics, high
aggressiveness and poor
prognosis.
Represent around 0.7% of all
breast tumors, some case series
report prevalences of up to
1.28-1.5%.
Rare variant of
adenocarcinoma that can
represent up to 8.7% of all
lobular carcinomas
EPIDEMIOLOGY
WHO CLASSIFICATION
2012
Breast cancer with
signet ring cell
differentiation
PRIMARYSIGNETRINGCELLCARCINOMAOFTHEBREAST
RARE TUMORS OF THE BREAST:

5. CLINICAL FEATURES
 Painless, unclear mass located in the upper outer quadrant of the
breast.
 Particularly, it may not be detected on manual examination or it
may present as a small diffuse nodule, accompanied or not by
changes in the nipple with edema, ulceration or telorrhoea, as well
as skin changes such as dimpling and orange peel.
Considered variants of lobular carcinoma, due
to the histological, ultrastructural, and
immunohistochemical similarities of both
entities, but the presence of mucins is a rare
finding in lobular carcinomas
Unusual
pattern of
metastasis
Gastroint
estinal
tract
Serous
Genital
tract
Immunohistochemical profile: positivity
for CK 7, hormone receptors, and
GCDFP protein help diagnose a breast
origin, and the negativity of these
markers, with positive immunostaining for
CK 20 and CEA, support the diagnosis of
gastrointestinal origin.