385
FIG. 11.67.
DCIS and microinvasive carcinoma.
A:
Car-
cinoma protrudes from a duct with solid DCIS. Note the
stromal reaction including minute blood vessels directed
toward the protruding carcinoma
.
In this plane of sec-
tion, the finding is ambiguous and not diagnostic of inva-
sion because this could be a tangential section of a small
secondary duct exiting the large duct. Immunostains for
basement membrane components, myoepithelial cells,
and cytokeratin are helpful in analyzing such foci.
B,C:
This focus from the same case as
(A)
provides stronger
evidence for microinvasion because there appears to be
greater disruption of the protruding epithelium includ-
ing isolated cell clusters
(B)
in the stroma. Note the small
blood vessel directed at the site of invasion
(C)
.
FIG. 11.68.
DCIS and microinvasive carcinoma.
A:
Two
isolated carcinoma cells (
arrow
) in the periductal stroma
adjacent to a tangentially sectioned duct containing DCIS.
B:
Disruption of the basement membrane is evident,
and there are carcinoma cells in the periductal stroma
(
arrows
).
C:
A larger focus of microinvasion (
upper right
)
with a marked lymphocytic reaction.
