Invasive breast carcinoma - IARC

A
B
C
Fig. 1.103 Papillary intraductal carcinoma. A Cystically dilated duct with arborescent papillary tumour. B Papillary structure lined by epithelial columnar cells.
C Two papillary structures lined by atypical cylindrical cells with formation of arcades. D Papillary structures are devoid of myoepithelial cells. Smooth muscle actin
(SMA) immunostaining highlights vascular structures in papillary fronds. Epithelial cells lining the papillary fronds are CK 5/6 negative (not shown).
D
the papillary processes are totally
devoid of a myoepithelial cell layer
re g a rdless of presence or absence of
notable epithelial proliferation, and/or
that any of the recognized patterns of
low grade DCIS occupies 90% or more
of the lesion.
These neoplasms can be either solitary
and central in location corresponding to
intracystic papillary carcinoma, or multifocal
within the TDLU and corre s p o n d
to the papillary type of DCIS.
Intracystic papillary carcinoma
Definition
This lesion is a variant of intraductal
p a p i l l a ry carcinoma, located within a
large cystic duct and characterized by
thin fibrovascular stalks devoid of a
myoepithelial cell layer and of a neoplastic
epithelial cell population with
histopathological features characteristic
of low grade DCIS.
ICD-O code 8504/2
Synonyms
Intracystic papillary carcinoma, noninvasive;
papillary intraductal carcinoma;
p a p i l l a ry ductal carcinoma in situ;
encysted papillary carcinoma.
Epidemiology
Less than 2% of breast carcinomas correspond
to intraductal papillary carcinomas
{413,1945}. The average age of
occurrence is around 65 (range, 34-92
years) {413,1618}.
Clinical and macroscopic features
On the basis of clinical presentation and
m a c ro s c o p y, there are no distinctive feat
u res that can separate papilloma fro m
p a p i l l a ry carcinoma, nonetheless, intracystic
papillary carcinomas tend to be larger.
Histopathology
Intraductal papillary carcinoma is a
p a p i l l a ry lesion usually of large size
(mean 2 cm, range 0.4-10 cm) located
within a large cystic duct characterized
by thin fibrovascular stalks devoid of
a myoepithelial cell layer and a neoplastic
epithelial cell population usually
presenting characteristics of low grade
DCIS. These cells are arranged in either
solid, cribriform, micropapillary or stratified
spindle cell patterns {413,1618,
1945}. Some may show a dimorphic cell
Fig. 1.104 Gross appearance of an intracystic papillary
breast carcinoma. Macroscopically, the distinction
between papilloma and papillary carcinoma
may be difficult.
Intraductal papillary neoplasms
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