PATHOLOGY IDENTIFICATION OFF MAMMOGRAMS
For location and identification of pathology, the breast is
divided into segments in the following ways:
‘BB’s are metallic markers
that is used in the United States to mark the nipple or palpable
mass for the Radiologist to locate and detect pathology. This shows
up as white dots/circles on the mammograms as a reference point.
3.1. Frequency and
Location of Breast Cancer
Maximum cases are in Upper Outer Quadrant and in the TDLUs (Terminal
Duct Lobular Unit).
3.2. Morphologic
Presentations
As you can see from the mammograms and diagrams, the breast tissue
comprises of small intricate structures so pathology can easily be
overlooked, especially if the film quality is not good. Not all
structures are cancers. Many structures or macro (big)
calcifications are often benign. Some basic forms of pathology and
morphology presentations are (Addendum 3):
3.2.1. Masses and
Densities
‘Masses’ differ from ‘Densities’ because ‘masses’ are seen on two
views whereas ‘densities’ are seen on one view only. Hence, two
views of each breast to identify this abnormality. Masses with
smooth rounded edge is generally a fluid-filled cyst that can be
confirmed by an ultrasound and aspirated to relieve pain for the
woman. Hard lesions with uneven edges might be reason for follow-up
procedures. A mass could be palpable (can feel it during a physical
breast exam) depending on the size and proximity to the skin
surface. A fat containing mass looks radiolucent on the mammogram.
Sometimes, it is very difficult for radiologists to differentiate
between a benign and a malignant mass off mammograms (as in Fig.
below), so additional imaging modalities and/or biopsy may be
required.
3.2.2. Micro
calcifications
Calcifications are small calcium deposits that can be detected on a
mammogram. Minute calcifications are called micro calcifications and
bigger ones are called macro calcificiations. The latter is
generally benign and does not need additional follow-up. Sometimes,
other structures mimic micro calcifications such as calcified
arteries that appear like ‘train tracks’. This is normal. Artifacts
on mammograms due to specs of dust may look like micro
calcifications, but the difference is that these specs are bright
and shiny whilst a micro calcification looks ‘milky white’.
Radiologists categorize the calcifications as malignant or benign
based on (1) the location of calcifications, (2) the arrangement
(linear or scattered or clusters) (3) the total number of micro
calcifications (4) the changes with respect to the previous
mammograms.
3.2.3. Spiculated
lesions
This is by far the most definitive way to detect cancer. As a cancer
cell proliferates, it shows up as a ‘star-shaped’ or ‘stellate’
lesion, with spiky lines radiating in all directions from a central
region. A white star shape is characteristic of a malignant stellate
lesion whereas the black star indicates a radial scar and
post-traumatic fat necrosis. In advanced cases, spicules that
approach the skin or muscle, cause retraction and localized breast
distortion.
Crossing structures (each
blood vessels and tissue), convergence of ducts at the nipple, or
past surgical scars may mimic a stellate lesion. Radiologists have a
set of criteria to narrow down the options (Refer to Addendum 3).
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