Invasive breast carcinoma - IARC

A
Papilloma may be subject to morphological
changes such as inflammation,
n e c rosis, myoepithelial hyperplasia,
apocrine, squamous, sebaceous, mucinous,
osseous and chondroid metaplasia
as well as usual intraductal hyperplasia
{148,893,1350,1945,2327,2420,2873}.
A pseudo-infiltrative pattern may be observed
at the periphery of these lesions
particularly in the sclerosing variant.
The myoepithelial cell layer may have an
uneven distribution both in areas of UDH,
ADH, and DCIS {2325}.
The entire range of ductal intraepithelial
proliferations may arise within, or secondarily
involve, a central papilloma. The
clinical implications of such lesions have
not at this time been fully established and
should be considered in the context of
the surrounding breast tissue.
Peripheral papilloma
Synonym
Microscopic papilloma.
Epidemiology
The average age at presentation of
peripheral papillomas is similar to that of
central papillomas or slightly younger
{401,1097,1945}.
B
C
Fig. 1.101 A Typical morphology of a papilloma of the breast. B Cytokeratin (34 βE12) staining decorates
myoepithelial and some epithelial cells. C Papilloma with atypical ductal hyperplasia (ADH). Note HHF-35
immunoreactive myoepithelial cells at the periphery of ADH.
Histopathology
Papillomas are characterized by an
a r b o rescent structure composed of
fibrovascular stalks covered by a layer of
myoepithelial cells with overlying epithelial
cells. In some lesions papillary and
ductal patterns coexist. When the ductal
pattern predominates and is associated
with marked sclerosis, the term sclerosing
papilloma may be used. Ductal
adenoma is considered by some as a
variant of generally sclerosing papilloma.
Clinical features
Peripheral papillomas are often clinically
occult. They rarely present as a mass and
nipple discharge is far less frequent in
this group {401}. They are also usually
mammographically occult, but they may
manifest as peripherally situated microcalcifications,
nodular prominent ducts or
multiple small peripheral well circ u m-
scribed masses {401}. Micro c a l c i f i c a t i o n s
may be located in the peripheral papillomas
or in adjacent non-papillary intraductal
proliferative lesions, e.g. ADH.
Macroscopy
Unless they are associated with other
changes, peripheral papillomas are usually
a microscopic finding.
Histopathology
Peripheral papillomas are usually multiple.
They originate within the TDLUs from
where they may extend into the larger
ducts {2092}. The histological features
are basically the same as for central
papillomas. Compared to central papillomas,
however, peripheral papillomas are
more frequently observed in association
Intraductal papillary neoplasms
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