Ductal Carcinoma
In Situ
347
FIG. 11.13.
DCIS, micropapillary.
Some epithelial fronds
have delicate fibrovascular centers.
A
B
C
FIG. 11.14.
DCIS, micropapillary.
Intraductal micropapillary
growth developing cribriform
(A,B)
and Roman bridge-like
(C)
structures.
medium-sized cells with high-grade round-to-oval nuclei
with speckled chromatin. Such neoplastic cells are generally
uniform, with centrally placed nuclei within which nucleoli
are inconspicuous. So-called “flat epithelial atypia” (in most
cases synonymous with atypical CCH) and
low-grade
DCIS
of the breast have been shown to share highly homologous
molecular and genomic profiles
118
; however, such data can
be interpreted as being reflective of the difficulty in distin-
guishing between the two entities, morphologically as well as
by molecular criteria, and the need to be conservative in the
diagnosis of low-grade DCIS.
Calcifications with distinctive crystalline, ossifying, and
laminated appearances tend to occur in CCH, leading to
mammographic detection. Patients with CCH may have tu-
bular carcinoma, LCIS, and invasive lobular carcinoma, as
well as micropapillary DCIS.
Cribriform
DCIS is a fenestrated epithelial proliferation
in which microlumens are formed by neoplastic epithelium
that bridges most or all of the duct lumen. Cribriform DCIS
can be found at all levels of the main duct system frommajor
ducts to terminal intralobular ductules. Extension into lobu-
lar epithelium (so-called “lobular cancerization”) or into the
main lactiferous ducts of the nipple is uncommon. Markedly
dilated ducts with cribriform DCIS can be mistaken for
women 35 to 55 years of age. The lesions are typically mul-
tifocal or multicentric and can be bilateral. Flat micropapil-
lary (“clinging”) DCIS should be diagnosed whenever a flat
epithelial proliferative process shows relatively small- to
