Invasive breast carcinoma - IARC

A
B
Fig. 1.158 Paget disease of the nipple. A Atypical cells with clear cytoplasm admixed with those with dense cytoplasm. B, C Immunostaining for cytokeratin 7 (B)
and ERBB2 (C) decorate the neoplastic cells predominantly located in the lower portion of the epidermis.
C
ters which are often closely packed in
the centre of the lesion and lower portion
of the epidermis but tend to be dispersed
in single cells at the periphery
and upper portion of the epidermis. The
underlying lactiferous ducts contain a
usually high grade DCIS that merges
with the PD. Rare l y, lobular intraepithelial
neoplasia is encountered. Even
when the in situ carcinoma is in the
deep breast tissue, an involved lactiferous
duct with or without skip areas can
almost always be identified by serial
s e c t i o n i n g .
An associated infiltrating carc i n o m a
occurs in one-third of patients who present
without a palpable mass and in more
than 90% of those with a palpable mass.
Special stains reveal the presence of
mucin in the Paget cells in a large number
of cases. Paget cells occasionally
contain melanin pigment granules as a
result of phagocytosis.
Immunoprofile
I m m u n o h i s t o c h e m i c a l l y, Paget cells
demonstrate similar pro p e rties to the
underlying intraductal carcinoma cells
with positive immunoreactivity for carc i-
n o e m b ryonic antigen, low molecular
weight cytokeratin and ERBB2. On
occasion, one of these antisera may be
negative. Squamous carcinoma is commonly
non-reactive for these antisera,
but rarely may be immunoreactive for
cytokeratin 7 {3128}. Contrary to malignant
melanoma, PD is usually S-100
p rotein and HMB45 negative. In PD,
TP53 and estrogen receptor may be
negative or positive, depending on the
i m m u n o p rofile of the corre s p o n d i n g
underlying carcinoma.
Differential diagnosis
PD occasionally poses diff e rential diagnostic
problems with malignant
melanoma due to the pagetoid pattern
of spread and the presence of pigment
granules and also with squamous cell
c a rcinoma in situ, due to the pro l i f e r a-
tion of atypical dark cells. The application
of histochemical techniques and
the use of immunostains will solve the
question in most cases.
Prognosis and predictive factors
The prognosis is dependent on the
p resence or absence of underlying
intraductal carcinoma and associated
invasive carcinoma in the deep bre a s t
t i s s u e .
106 Tumours of the breast