Invasive breast carcinoma - IARC

A
Fig. 1.157 Syringomatous adenoma of the nipple. A Irregular shaped glandular structures are present between smooth muscle bundles. B Actin stains the fascicles
of smooth muscle but the syringoma is unstained.
B
S y n o n y m
Infiltrating syringomatous adenoma.
Epidemiology
Syringomatous adenoma (SyT) is a rare
lesion {1365,2414,2816}. While only 24
cases have been reported under this
designation {98}, other cases have been
re p o rted as examples of low grade
adenosquamous carcinoma {2431,2816,
2995}. The age range is from 11 to 67
years with an average age of 40 years.
Clinical features
SyA presents as a firm discrete mass
(1–3 cm) situated in the nipple and subareolar
region {269,1365}.
Macroscopy
The lesion appears as a firm, ill defined
nodule.
Histopathology
SyA consists of nests and branching
cords of cells, glandular structures and
small keratinous cysts permeating the
nipple stroma in between bundles of
muscle as well as in perineural spaces
{1365,3056}. Extensions of the tumour
may be present at a great distance from
the main mass with intervening normal
tissue. Cytologically, most of the proliferating
elements appear bland with scant
eosinophilic cytoplasm and re g u l a r
round nuclei. The cells lining the gland
lumina are cuboidal or flat. Frequently
the glandular structures display two layers
of cells: i.e. inner luminal and outer
cuboidal basal cells occasionally containing
smooth muscle actin. Mitoses are
rare and necrotic areas are absent. The
stroma is usually sclerotic, but myxoid
areas containing spindle cells are frequent.
Differential diagnosis
This includes tubular carcinoma (TC)
which rarely involves the nipple and low
grade adenosquamous carcinoma which
occurs in the breast parenchyma {2431}.
Prognosis and predictive factors
Recurrence has been reported {269}.
Optimal treatment is excision with generous
margins.
Paget disease of the nipple
Definition
The presence of malignant glandular
epithelial cells within the squamous
epithelium of the nipple, is almost always
associated with underlying intraductal
carcinoma, usually involving more than
one lactiferous duct and more distant
ducts, with or without infiltration, deep in
the underlying breast. Paget disease
(PD) of the nipple without an underlying
carcinoma is rare.
ICD-O code 8540/3
Epidemiology
PD may be bilateral and may occur in
either gender but at a relatively higher
rate in men. The incidence is estimated
at 1-4.3% of all breast carcinomas.
Aetiology
The glandular nature of the neoplastic
cells in PD is confirmed by electro n
m i c roscopic studies that show intracytoplasmic
lumen with micro v i l l i
{ 2 5 05}. Immunohistochemical studies
c o n f i rm that Paget cells have the same
phenotype as the underlying intraductal
carcinoma cells {530,1423}.
Suggested mechanisms of development
are: a) intraepithelial e p i d e r-
m o t ropic migration of malignant cells of
intraductal carcinoma to the epiderm i s ;
b) direct extension of underlying intraductal
carcinoma to the nipple and
overlying skin; and c) in situ neoplastic
t r a n s f o rmation of multi-potential cells
located in the basal layer of the lactiferous
duct and epiderm i s .
Clinical features
Depending on the extent of epiderm a l
involvement, the skin may appear unremarkable
or show changes ranging
f rom focal reddening to a classical
eczematous appearance, which may
extend to the areola and adjacent epid
e rmis. There is sometimes retraction of
the nipple.
Histopathology
In the epidermis, there is proliferation of
atypical cells with large nuclei and
abundant clear or focally dense cytoplasm.
They are disposed in small clus-
Tumours of the nipple 105