Invasive breast carcinoma - IARC

Fig. 1.141 Angiosarcoma after breast conserving
treatment. The spongy, haemorrhagic mass contains
occasional solid areas. In this case, the neoplasm
involves the breast parenchyma as well as
the skin.
reliable criterion upon which to make a
histological distinction between tumours
derived from endothelia of blood and
lymphatic vessels.
Epidemiology
Mammary angiosarcoma can be subdivided
into 1) Primary (de novo) forms in
the breast parenchyma; 2) Secondary in
the skin and soft tissues of the arm following
ipsilateral radical mastectomy
and subsequent lymphoedema - the
S t e w a rt Treves (S-T) syndrome; 3)
Secondary in the skin and chest wall following
radical mastectomy and local
radiotherapy; 4) Secondary in the skin or
b reast parenchyma or both following
conservation treatment and radiotherapy.
Angiosarcomas, as with other sarcomas
of the breast, are rare and their incidence
is about 0.05% of all primary malignancies
of the organ {2876}. While the incidence
of primary breast angiosarcomas
has remained constant, the incidence of
secondary forms has changed. S-T synd
rome has dramatically declined in
recent years in institutions in which more
conservation surgical treatments have
been adopted, while angiosarcomas of
the breast developing after conserving
s u r g e ry with supplementary radiation
therapy have been diagnosed since the
late 1980s {570}.
Primary (de novo) angiosarcoma of
breast parenchyma
In patients with primary angiosarcoma,
the age ranges from 17 to 70 years
(median 38 years) with no prevalence of
laterality {2436}. The tumours are deeply
located in the breast tissue {2784}.
Approximately 12% of patients present
with diffuse breast enlargement {2876}.
When the tumour involves the overlying
skin a bluish-red discoloration may
ensue. Imaging is of little help {1656,
2564,3118}.
Macroscopy
Angiosarcomas vary in size from 1 to 20
cm, averaging 5 cm {2425}, have a
spongy appearance and a rim of vascular
engorgement which corresponds to a
zone of well differentiated tumour. Poorly
differentiated tumours appear as an ill
defined indurated fibrous lesion similar to
that of any other poorly differentiated sarcoma.
Angiosarcomas must be sampled
extensively to look for poorly differentiated
areas that on occasion constitute the
minority of a tumour.
Histopathology
Two systems have been used to grade
angiosarcomas of the breast {717,1847}.
Although very similar, the one proposed
by Donnell et al. {717} has gained wide
impact as it was tested in a large number
of patients with adequate follow up
{2436}.
Grade I (well differentiated) angiosarcomas
consist of interanastomosing vascular
channels that dissect the interlobular
stroma. The neoplastic vessels have very
wide lumina filled with red blood cells.
The nuclei of the endothelium lining the
neoplastic vessels are prominent and
hyperchromatic. Care must be taken to
differentiate grade I angiosarcoma from
benign vascular tumours.
Grade III (poorly differentiated) angiosarcomas
are easy to diagnose as interanastomosing
vascular channels are
i n t e rmingled with solid endothelial or
spindle cell areas that show necrotic foci
and numerous mitoses. In a grade III
angiosarcoma, more than 50% of the
total neoplastic area is composed of
solid and spindle cell components without
evident vascular channels {2425}.
A tumour qualifies as grade II (intermediately
differentiated) angiosarcoma when
at least 75% of the bulk of the tumour is
formed by the well differentiated pattern
seen in grade I, but in addition there are
solid cellular foci scattered throughout
the tumour.
Clinical feature
The average age of patients with grade I
angiosarcomas is 43 years while 34 and
29 years are the respective figures for
grade II and III angiosarcomas {717}.
A
B
Fig. 1.142 Angiosarcoma after breast conserving treatment. A As in the majority of cases, this is a poorly differentiated
angiosarcoma in which vascular channels are hard to see. B Immunostaining for the endothelial
marker CD31 clearly demonstrates the solid areas of endothelial cells with occasional vascular channels.
Immunoprofile
Factor VIII, CD34 and CD31 are the most
widely used antibodies that characterize
endothelial differentiation. While present
Mesenchymal tumours
95