Invasive breast carcinoma - IARC

population (featuring epithelial and myoepithelial
differentiation) which may be
mistaken for two cell types {1618}. Less
frequently, the epithelial cell component
presents the characteristics of intermediate
or high grade DCIS. Concomitant
DCIS may be present in the surrounding
breast tissue. A complete absence of the
myoepithelial cell layer in the papillary
processes indicates a carcinoma; the
presence of myoepithelial cells does not
invariably exclude the diagnosis of intraductal
papillary carcinoma, however. A
myoepithelial cell layer is usually present
in the lining of the duct wall into which the
papillary carcinoma proliferates.
Solid and transitional cell variants have
been described {1752,1905}. The distinctive
features of the former are pro d u c t i o n
of extracellular and intracellular mucin,
association with mucinous carc i n o m a
and often a spindle cell population.
A r g y rophilia and neuroendocrine feature s
have been noted in a large number of the
solid cases {694,1752,2955}. The transitional
cell variant is characterized by proliferation
of sheets of transitional type
cells overlying the fibrovascular core s .
As with benign papillomas entrapment of
epithelial structures within the wall can
result in a pseudoinvasive pattern. A
definitive diagnosis of invasive carcinoma
associated with intracystic papillary
carcinoma should only be considered
when neoplastic epithelial structures infiltrate
the breast tissue beyond the fibrous
wall and have one of the recognized patterns
of invasive carcinoma. Following a
needle biopsy (fine needle aspiration or
core biopsy), epithelial displacement into
the needle tract, scar tissue or lymphatic
spaces can mimic invasion {3231}.
Genetic alterations
Genetic alterations in the form of interstitial
deletions {701}, LOH {1671}, numerical
and structural alterations at chromosomes
16q and 1q with fusion of chromosomes
16 and 1 [der(1;16)] {2961}
have been described, but the significance
of these alterations are as yet,
unclear.
Prognosis and predictive factors
Intraductal papillary carcinoma in the
absence of concomitant DCIS or invasive
carcinoma in the surrounding breast tissue
has a very favourable prognosis with
no reported lymph node metastases or
disease-related deaths. The presence of
A
DCIS or invasive carcinoma in the surrounding
breast tissue are associated
with an increase in frequency of local
recurrence (in situ or invasive) in the form
e r, and an increase in local and
metastatic rates in the latter {413}.
Complete excision of intraductal papillary
carcinoma with adequate sampling
B
C
Fig. 1.105 Intracystic papillary carcinoma. A Left breast, medio-lateral oblique projection showing a 3x3 cm,
solitary, high density circular mass in the lower half of the breast. B Breast ultrasound demonstrates intracystic
growth. C Intracystic papillary carcinoma in situ. Large section histology.
A
C
Fig. 1.106 Ductal intracystic papillary carcinoma. A Typical papillary pattern. B Cribriform pattern.
C Stratified columnar cells, in the absence of myoepithelial cells. D Transitional cell-type pattern.
B
D
of the lesion and surrounding breast tissue
is mandatory for treatment and
appreciation of subsequent breast cancer
risk.
Prognosis and management of papillary
type of DCIS is similar to that of common
DCIS and is dealt with in the corresponding
chapter.
80 Tumours of the breast