378
Chapter 11
CK5/6 positive) in 8% of DCIS and found it to be associ-
ated with unfavorable prognostic variables, including high-
grade nuclei, p53 overexpression, and elevated proliferation
index.
202
Basal-like DCIS using the immunohistochemical
profile of (triple negative, CK5/6 positive and EGFR positive
as a surrogate for gene expression profiling) has been shown
to have a doubled, yet statistically insignificant, risk of local
recurrence and developing invasive cancer compared with
other types. In this study of 392 patients, 32 (8.2%) were
basal-like.
244
No significant difference has been detected in the ampli-
fication of certain key genes, including
ESR1
that encodes
for ER,
CCND1
that encodes for cyclin D1, and
MYC
that
encodes for a helix-loop-helix/leucine zipper protein, be-
tween DCIS and invasive breast carcinoma.
245
This indicates
that these genes are implicated in cancer development but,
perhaps, not in the initiation of invasive carcinoma.
Needle Core Biopsy
FS examination is not appropriate for a needle core biopsy
of a nonpalpable mammographically detected lesion, unless
there are exceptional circumstances.
246
Grading of DCIS in
paraffin sections of needle core biopsies is generally accu-
rate, but the probability of structural variability increases
with the size of the lesion.
Calcifications and necrotic debris may become dislodged
in a needle core biopsy specimen, and rarely this material is
the only component of DCIS in the sample (Fig. 11.60). In
this circumstance, serial sections should be prepared. An ex-
cisional biopsy should be considered, even if no epithelial el-
ements of carcinoma are detected in serial sections that show
displaced calcification of a type (i.e., amid ghost cells and
karyorrhectic debris) that might occur in DCIS. A dislodged
fragment of DCIS that becomes embedded in fat or stroma
as part of a needle core biopsy sample may be mistaken for
invasive carcinoma (Fig. 11.61).
“Healed” DCIS and end-stage periductal mastitis can
both result in indistinguishable scarred ductal structures
with calcifications (Fig. 11.62). When this type of structure
is found in a needle core biopsy specimen, multiple serial
sections should be prepared to search for scant foci of carci-
noma that may be present. The limited epithelial abnormali-
ties found in some of these cases may result in a diagnosis of
ADH. A surgical excision is indicated for the latter diagnosis
and in some situations may be appropriate when ductal scars
are present without epithelial atypia if the mammographic
findings raise concern about carcinoma.
The distinction between invasive carcinoma and SA or
radial sclerosing lesions can be challenging in needle core bi-
opsy specimens. This difficulty is compounded when DCIS
arises in sclerosing lesions (Fig. 11.63). It is important to
consider this potential diagnostic pitfall and to employ im-
munohistochemical stains to define the distribution of myo-
epithelial cells in the specimen. Incomplete samples of radial
sclerosing lesions obtained in needle core biopsy samples are
difficult to assess for intraductal or invasive carcinoma, and
they may be reported as atypical hyperplasia.
A needle core biopsy specimen cannot be relied upon to
measure the size of a DCIS lesion, even if the procedure is
performed for calcifications alone and calcifications are no
longer present in a follow-up mammogram. The needle bi-
opsy specimen rarely provides a single intact sample of the
lesion, and it is not feasible to reassemble the DCIS foci from
multiple samples to obtain a single measurement.
The diagnosis of DCIS in a needle core biopsy speci-
men does not exclude the possibility of invasive carcinoma
in the affected breast. The reported frequency of invasive
carcinoma detected in excisional biopsies performed after a
needle core biopsy diagnosis of DCIS was 15% to 27%.
247–253
The diagnosis of DCIS without invasion was reported to be
more reliable with directional vacuum-assisted biopsy pro-
cedure than with the automated needle biopsy system.
249
The diagnosis of DCIS on needle core biopsies can in-
fluence the extent of the subsequent surgery. Dillon et al.
254
FIG. 11.60.
DCIS, needle core biopsy.
A:
Fragmented calcification surrounded by necrotic debris
and sparse isolated atypical cells in blood were the significant findings in a needle core biopsy
specimen.
B:
Subsequent surgical excision revealed micropapillary DCIS with calcifications.
