Invasive breast carcinoma - IARC

are rare. Some require complete involvement
of a single duct cross section by
characteristic cells and arc h i t e c t u re ,
while others require either involvement of
two spaces or one or more duct cross
sections exceeding 2 mm in diameter.
Microcalcifications are generally of the
psammomatous type. There may be
occasional desquamated cells within the
ductal lumen but the presence of necrosis
and comedo histology are unacceptable
within low grade DCIS.
DCIS with micro p a p i l l a ry pattern may be
associated with a more extensive distribution
in multiple quadrants of the
b reast compared to other variants
{2584}. The working gro u p ’s minimal criteria
for diagnosis of low grade DCIS are
shown in Table 1.14.
Intermediate grade DCIS
I n t e rmediate grade DCIS lesions are
often composed of cells cytologically
similar to those of low grade DCIS, forming
solid, cribriform or micro p a p i l l a ry
p a t t e rns, but with some ducts containing
intraluminal necrosis. Others display
nuclei of intermediate grade with occasional
nucleoli and coarse chro m a t i n ;
n e c rosis may or may not be pre s e n t .
The distribution of amorphous or laminated
microcalcifications is generally
similar to that of low grade DCIS or it
may display characteristics of both low
grade and high grade patterns of microc
a l c i f i c a t i o n .
High grade DCIS
High grade DCIS is usually larger than
5 mm but even a single