Invasive breast carcinoma - IARC

A
B
Fig. 1.09 Mammographic demonstration of the evolution of a poorly differentiated invasive ductal carcinoma, a circular tumour mass on the mammogram.
A Non-specific density in the axillary tail of the right breast, undetected at screening. B 18 Months later: >30 mm ill defined, high density lobulated tumour, mammographically
malignant. Metastatic lymph nodes are seen in the axilla. C Large section histology of the tumour.
C
masses, parenchymal deformity and calcification
with or without a mass lesion.
By far the most common manifestation of
breast cancer on the mammogram is
tumour mass without calcifications. The
mammographic histological corre l a t i o n
of 1,168 open surgical biopsies at Falun
Central Hospital, Sweden, included 866
Table 1.03
Mammographic appearance of histologically
malignant breast lesions.
Stellate and circular 64%
without calcifications
Stellate and circular 17%
with calcifications
Calcifications only 19%
Table 1.04
Spectrum of histological diagnosis corresponding
to mammographic circular/oval lesions.
Invasive ductal carcinoma, NOS 59%
Medullary carcinoma 8%
Mucinous carcinoma 7%
Intracystic carcinoma 5%
Tubular carcinoma 4%
Invasive lobular carcinoma 4%
Other diagnoses 13%
histologically proven malignancies. As
seen in Table 1.03, the mammograms of
these breasts cancer showed:
1) Stellate or circular tumour mass with
no associated calcifications in 64% of the
cases.
2) An additional 17% had both calcifications
and tumour mass.
3) Only calcifications without associated
tumour mass accounted for less than
20% of all malignancies detectable on
the mammogram.
Grading of invasive carcinoma
Invasive ductal carcinomas and all other
invasive tumours are routinely graded
based on an assessment of tubule/gland
f o rmation, nuclear pleomorphism and
mitotic counts.
Many studies have demonstrated a significant
association between histological
grade and survival in invasive breast carcinoma.
It is now recognized as a powerful
prognostic factor and should be
included as a component of the minimum
data set for histological re p o rting of
breast cancer {779,1190}. Assessment of
histological grade has become more
objective with modifications of the Patley
& Scarff {2195} method first by Bloom
and Richardson {293} and more recently
by Elston and Ellis {777,2385}.
Method of grading
T h ree tumour characteristics are evaluated;
tubule formation as an expression of
glandular diff e rentiation, nuclear pleomorphism
and mitotic counts. A numerical
scoring system of 1-3 is used to ensure
that each factor is assessed individually.
When evaluating tubules and glandular
acini only structures exhibiting clear central
lumina are counted; cut off points of
75% and 10% of glandular/tumour area
are used to allocate the score.
Nuclear pleomorphism is assessed by
reference to the regularity of nuclear size
and shape of normal epithelial cells in
adjacent breast tissue. Increasing irregularity
of nuclear outlines and the number
and size of nucleoli are useful additional
features in allocating scores for pleomorphism.
Evaluation of mitotic figures requires care
and observers must count only defined
mitotic figures; hyperc h romatic and
pyknotic nuclei are ignored since they
are more likely to represent apoptosis
than proliferation. Mitotic counts require
standardization to a fixed field area or by
using a grid system {1984}. The total
number of mitoses per 10 high power
fields. Field selection for mitotic scoring
should be from the peripheral leading
edge of the tumour. If there is heterogeneity,
regions exhibiting a higher frequency
of mitoses should be chosen.
Field selection is by random meander
through the chosen area. Only fields with
a re p resentative tumour cell burd e n
should be assessed.
The three values are added together to
produce scores of 3 to 9, to which the
grade is assigned as follows:
18 Tumours of the breast