Ductal Carcinoma
In Situ
339
FIG. 11.4.
DCIS with basal lamina and myoepithelial cells.
A–C
are from the same specimen.
A:
The basal lamina is
highlighted by the immunostain for type IV collagen. Re-
activity is also present around small blood vessels, includ-
ing vessels in the upper two ducts.
B:
Laminin reactivity
shown here has the same distribution as type IV collagen.
C:
There is no reactivity for SMA indicating the absence
of myoepithelium in this DCIS.
D:
Basement membrane
is highlighted by the reticulin stain.
E:
In this example of
cribriform DCIS, myoepithelial cells display reactivity for
the SMA.
ring cells
, usually associated with lobular carcinoma, also oc-
cur in DCIS, most often in the papillary and cribriform types
(Fig. 11.5). The presence of signet ring cells with cytoplasmic
mucin demonstrated with the mucicarmine, periodic acid–
Schiff (PAS), or Alcian blue stains is strong evidence for a
diagnosis of DCIS. These cells are present only very rarely in
hyperplastic duct lesions. Signet ring cells have eccentric nu-
clei that are often along the nuclear border, which abuts on
the cytoplasmic mucin vacuole. A minute droplet of secre-
tion may be apparent in the vacuole. Intracytoplasmic mucin
sometimes imparts a diffuse pale blue color to the cytoplasm
of carcinoma cells without forming distinct vacuoles. Non-
specific clear holes in the cytoplasm can be mistaken for sig-
net ring vacuoles. These cytoplasmic defects, sometimes the
site of glycogen accumulation, are not reactive with stains for
mucin; they usually do not indent the nucleus, and there is
ordinarily no secretion evident in the lumen.
Apocrine
cytology is encountered in all of the structural
types of DCIS (Fig. 11.6). Apocrine DCIS cells have abun-
dant cytoplasm that ranges from granular and eosinophilic
