Unusual Clinical Presentation of Carcinoma
925
FIG. 33.35.
Primary inflammatory carcinoma, cutaneous pathology.
A:
A cluster of carcinoma cells
is present in a lymphatic space in the dermis.
B:
A solitary cluster of cells “suspicious for carcinoma”
is seen in this punch biopsy of skin performed to rule out inflammatory carcinoma. The differential
diagnosis includes carcinoma, histiocytes, and endothelial hyperplasia with “telescoping.” The endo-
thelial lining cells display immunoreactivity for D2-40 and factor VIII, and the “suspicious” cells are
cytokeratin (ck) positive. These findings are diagnostic of dermal lymphatic involvement by carcinoma.
A
B
A lymphoplasmacytic reaction may be encountered in
the carcinoma or in the surrounding breast, but it does not
differ in intensity, pattern, or frequency from the findings
in patients with noninflammatory carcinoma.
234,268,269
The
intensity of the inflammatory reaction in the breast and
skin is usually similar, but these reactive components have
not been found to correlate with the severity and distribu
tion of the clinical cutaneous manifestations of the disease.
That is, patients with the most marked lymphoplasmacytic
reaction do not necessarily have the most intense cutaneous
erythema or the most severe edema. There is also no direct
relationship between the number of lymphatic tumor em
boli or the extent of vascular distension and the clinical find
ings. Neutrophils, eosinophils, or numerous mast cells are
not a common feature of IBC.
Because the cutaneous manifestations of IBC are so clini
cally striking, there has been a great deal of interest in the
microscopic pathology of the skin. An incisional biopsy of
the skin is often performed for diagnostic purposes, but the
diagnosis of carcinoma can be made easily by needle biopsy
of the breast if there is an underlying palpable mass. It is not
necessary to obtain a skin biopsy to establish the diagnosis
of IBC when a patient presents with characteristic clinical
findings and a biopsy-proven breast carcinoma.
The skin often displays a variety of histologic alterations
associated with IBC (Fig. 33.35). The collagenous reticular
dermal layer is broader than normal because of increased
amounts of collagen and edema. Dilation of lymphatics
tends to be prominent in the papillary and reticular dermis,
and intralymphatic tumor emboli can be found at either
level of the dermis. When present, a lymphoplasmacytic re
action is localized around dilated lymphatic channels.
The microscopic pathology of the skin varies greatly
among patients with IBC. Histologic features of the skin may
not correlate with the clinical findings. Samples of skin from
within and outside the zone of erythema and edema may
appear histologically similar, with lymphatic tumor emboli
detectable in areas that appear clinically uninvolved. When
carcinoma is found in the skin of a patient with primary IBC,
it is usually limited to lymphatic emboli. Extralymphatic
dermal tumor infiltrates are uncommon. FNA in suspected
cases of IBC presenting without a palpable mass may be suc
cessful in establishing the diagnosis if samples taken from all
four quadrants with “extra passes in the antigravity areas are
attempted.”
270
In some patients with the classical clinical appearance
of IBC, tumor may not be found in biopsy samples from
the skin, even if serial sections of the specimen are prepa
red.
235,236,237,269
In one study, the skin biopsy specimen was
reportedly negative in 50% of IBC patients.
236
Thus, no pat
tern of histologic findings is specifically associated with the
clinical diagnosis of primary IBC.
“Inflammatory recurrent carcinoma” (secondary inflam
matory carcinoma) is usually accompanied by nodules and
plaques of invasive carcinoma in the dermis of the skin, as
well as intralymphatic tumor emboli (Fig. 33.36). In some
of these cases lymphatic tumor emboli are inconspicuous
or not detectable. Clinically, erythema and edema occur
equally in the skin over and around palpable dermal tumor
infiltrates, regardless of the presence of dermal lymphatic
tumor emboli.
A review of the primary lesions in patients who developed
an inflammatory recurrence suggested some predisposing
features.
234
All patients initially had primary infiltrating duct
carcinomas, including a disproportionately high number
with apocrine cytology. Inflammatory recurrence was rarely
found following treatment of papillary, medullary, and mu
cinous carcinomas. Although these patients did not exhibit
