Invasive breast carcinoma - IARC

myoepithelial cells in fibro a d e n o m a s ,
along with mast cells within the myxoid
stroma, helps in its recognition.
In mucocoele-like lesions, the presence
of myoepithelial cells adhering to the
strips of cells floating in the lakes of
mucus serves as an important clue to
their benign nature; the cell clusters in
mucinous carcinoma are purely epithelial.
The presence of ducts variably distended
by mucinous material adjacent to
a mucocoele is another helpful clue in
distinguishing mucocoele-like lesions
from mucinous carcinomas.
Immunoprofile and ploidy
Typically mucinous carcinoma is estrogen
receptor positive {2669}, while less
than 70% {691} are pro g e s t e rone re c e p-
tor positive. Nearly all pure mucinous carcinomas
are diploid, while over 50% of
the mixed variety are aneuploid {2933}.
Prognosis and predictive factors
Prognostic factors relevant to breast carcinomas
in general are also applicable to
pure mucinous carcinomas. Tumour cellularity
has also been implicated in that
cellular tumours are associated with a
worse prognosis {502}. The presence or
absence of argyrophilic granules had no
prognostic significance in two studies
{2590,2934}. In general, pure mucinous
carcinomas have a favourable prognosis
{844,2590,2934}. The ten-year survival
ranges from 80% {1498} to 100%
{844,2053}. Pure mucinous carcinomas
have a far better prognosis than the
mixed variety with at least a 18% difference
in survival rates noted in several
studies {1498,2053,2934}. About 10% of
women with the pure form die of their
cancer compared to 29% of those with
the mixed type {1498,2053}. A similar difference
also exists in the incidence of
axillary node metastases for pure and
mixed types; only 3-15% of the pure variety
show axillary node metastases comp
a red to 33-46% of the mixed type
{82,1498,2338}. Late distant metastases
may occur {502,2447,2934}.
A rare cause of death among women
with mucinous carcinoma is cere b r a l
infarction due to mucin embolism to the
cerebral arteries {2944}.
Mucinous cystadenocarcinoma
and columnar cell mucinous
carcinoma
Definition
A carcinoma composed of generally tall,
columnar cells with basally located bland
nuclei and abundant intracytoplasmic
mucin that appears either cystic (mucinous
cystadenocarcinoma) or solid
(columnar cell mucinous carcinoma) to
the naked eye.
ICD-O code
Mucinous cystadenocarcinoma 8470/3
Epidemiology
Only four examples of mucinous cystadenocarcinoma
and two of the solid
columnar cell type have been reported
{1486}. They occurred in women 49 to 67
years of age.
Clinical features
The clinical features of mucinous cystadenocarcinomas
are similar to common
infiltrating ductal carcinomas.
Macroscopy
The tumours vary in size from 0.8 to 19
cm, are cystic and display a gelatinous
appearance with abundant mucoid
material simulating an ovarian mucinous
tumour.
Histopathology
M i c ro s c o p i c a l l y, both of these variants,
a re composed of tall columnar mucinous
cells with abundant intracytoplasmic
mucin and basal nuclei. In the
A
A
B
B
Fig. 1.31 Mucinous carcinoma. A Hypercellular
variant with large clusters of densely packed
malignant cells. B Hypocellular variant. Lakes of
mucus are separated by fibrous septae. A few isolated
or clusters of carcinoma cells are floating in
the mucus lakes.
C
Fig. 1.32 A Mucinous cystadenocarcinoma. Papillary processes lined by mucinous columnar cells protude
into cystic spaces. B Mucinous cystadenocarcinoma. Many of the invasive cells are immunoreactive to
CK34βE12. C Combined mucinous and infiltrating ductal carcinoma. A favourable prognosis associated with
pure mucinous carcinoma is no longer expected when it is admixed with regular infiltrating duct carcinoma.
D Signet ring cell carcinoma. The invasive cells assume a lobular growth pattern and contain abundant
intracytoplasmic mucin conferring a signet-ring cell appearance to the cells.
D
Invasive breast cancer
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