Invasive breast carcinoma - IARC

Macroscopy
Fisher et al. reported that invasive papillary
carcinoma is grossly circumscribed
in two-thirds of cases {879}. Other invasive
papillary carcinomas are gro s s l y
indistinguishable from invasive bre a s t
cancers of no special type.
Histopathology
Of the 1,603 breast cancers reviewed in
the NSABP-B04 study, 38 had papillary
f e a t u res, and all but 3 of these were
" p u re," without an admixture of other histologic
types {879}. Micro s c o p i c a l l y,
expansile invasive papillary carc i n o m a s
a re characteristically circ u m s c r i b e d ,
show delicate or blunt papillae, and show
focal solid areas of tumour growth. The
cells typically show amphophillic cytoplasm,
but may have apocrine feature s ,
and also may exhibit apical "snouting" of
cytoplasm similar to tubular carc i n o m a .
The nuclei of tumour cells are typically
i n t e rmediate grade, and most tumours
a re histologic grade 2 {879}. Tumour stroma
is not abundant in most cases, and
occasional cases show prominent extracellular
mucin production. Calcifications,
although not usually evident mammog
r a p h i c a l l y, are commonly seen histologi
c a l l y, but usually are present in associated
DCIS. DCIS is present in more than
75% of cases, and usually, but not exclus
i v e l y, has a papillary pattern. In rare
lesions in which both the invasive and in
situ components have papillary feature s ,
it may be difficult to determine the re l a t i v e
p ro p o rtion of each. Lymphatic vessel
invasion has been noted in one third of
cases. Microscopic involvement of skin or
nipple was present in 8 of 35 cases
(23%), but Paget disease of the nipple
was not observed {879}.
E s t rogen receptor positivity was observed
in all 5 cases of invasive papillary
c a rcinoma examined in one study, and
p ro g e s t e rone receptor positivity in 4 of 5
(80%) {2351}. In a review of cytogenetic
findings in 5 examples of invasive papill
a ry carcinoma, 60% exhibited re l a t i v e l y
simple cytogenetic abnormalities {40}. In
addition, none of the 4 examples of papi
l l a ry carcinomas examined in two re c e n t
re p o rts were associated with either TP53
p rotein accumulation or ERBB2 oncoprotein
overe x p ression {2440,2750}.
Clinical course and prognosis
T h e re are only limited data on the pro g-
nostic significance of invasive papillary
A
Fig. 1.36 Papillary carcinoma with invasion. A Overview of an intraductal papillary carcinoma, present at
the centre, with invasive carcinoma apparent in the upper right side of the lesion. B Higher magnification
shows an infiltrating duct carcinoma pattern by the invasive component of the lesion while the in situ region
is clearly papillary.
c a rcinoma {868,871,879}. Among 35
patients with this tumour in the NSABP-
B04 trial, after 5 years median follow-up,
t h e re were only 3 treatment failure s ,
including 1 patient who died fro m
metastatic papillary carcinoma. These
survival data were similar to those
re p o rted in patients with pure tubular
and mucinous carcinomas in this study
{879}. A later publication updating the
NSABP-B04 results at 15 years re v e a l e d
that patients with "favourable" histology
tumours (including invasive papillary
c a rcinomas) still had significantly better
survival in univariate analysis, but
tumour histology was not an independent
predictor of survival in multivariate
analysis {871}. However, node-negative
patients with invasive papillary carc i n o-
mas enrolled in the NSABP-B06 trial
experienced improved survival after 10
years follow-up compared to patients
with carcinomas of no special type, and
tumour histology was an independent
p redictor of survival in multivariate
analysis {868}.
Invasive micropapillary
carcinoma
Definition
A carcinoma composed of small clusters
of tumour cells lying within clear stromal
spaces resembling dilated vascular
channels.
ICD-O code 8507/3
B
Epidemiology
C a rcinomas with a dominant micro p a p i l-
l a ry growth pattern account for less than
2% of all invasive breast cancers {707,
1715,1982,2194,2229}. The term invasive
micro p a p i l l a ry carcinoma was
coined by Siriaunkgul and Ta v a s s o l i
who first described nine examples of
this lesion {707}. While quite rare in its
p u re form, focal micro p a p i l l a ry gro w t h
has been re p o rted in 3-6% of more common
types of invasive carc i n o m a s
{1982,2194}. It occurs in the same age
range as invasive ductal carcinoma of
no special type.
Clinical features
Invasive micropapillary carcinoma usually
presents as a solid mass. Axillary
lymph node metastases are present at
first presentation in 72-77% {707,1715,
1982,2194,2229,3049} .
Macroscopy
Pure micropapillary carcinoma has a lobulated
outline due to the expansive mode
of growth.
Histopathology
Micropapillary carcinoma consists of hollow
aggregates of malignant cells, which
on cross section have the appearance of
tubules with diminished or obliterated
lumens rarely containing pyknotic nuclei.
These tumour cell cluster lie within artifactual
stromal spaces caused by shrinkage
of the surrounding tissue. The stromal
spaces lack an endothelial lining and
may be part of a speculated "missing
lymphatic labyrinth" in mammary stroma
{1152}. Nuclear pleomorphism is moderate,
mitotic activity low, and there is neither
necrosis nor lymphocytic reaction. In
n o n - p u re tumours, gradual or abrupt
transitions from typical invasive ductal
carcinoma to the micropapillary components
are found. Peritumoural angioinvasion
may be present in up to 60% of
cases. Intravascular tumour emboli,
Invasive breast cancer
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