DOCTOR'S VIEW ARCHIVE
Types of Breast Cancer
Question and Answer with Ralph Maeda, M.D.
Question:
What are the types of breast cancers?
Breast cancer is not just one disease, but rather is a general term used to
describe a number of different types of cancers that occur in the breast. The majority of breast cancers can be classified into one of
the
following categories; infiltrating ductal carcinoma,
infiltrating lobular
carcinoma, ductal carcinoma in situ, lobular carcinoma in situ,
inflammatory carcinoma, Paget's disease, and cystosarcoma
phyllodes. There
are other tumors of the breast, such as angiosarcoma, squamous
cell cancer
and lymphoma, but they are quite rare. These categories are
based on the
microscopic appearance of the breast tissue obtained with a
biopsy sample.
Infiltrating Ductal Carcinoma
Infiltrating Ductal Carcinoma begins in the cells forming the
ducts of
the breast. It is the most common form of breast cancer,
comprising about
65-85% of all cases. On a mammogram, invasive ductal carcinoma
is usually
found as an irregular mass, or as a group of small white
irregular dots
called microcalcifications, or a combination of both. It may
also appear
as a lump in the breast. On physical examination, this lump
usually feels
much harder or firmer than other benign causes of lumps in the
breast.
Infiltrating Lobular Carcinoma
Infiltrating Lobular Carcinoma comprises 5 to 10 percent of
breast
cancers. This type of breast cancer can appear similar to
infiltrating
ductal carcinoma on mammography, but on examination of the
breast there is
usually not a hard mass, but rather a vague thickening of the
breast
tissue. Lobular carcinoma can occur in more than one site in
the breast
(multicentric) or in both breasts simultaneously
(bilateral).
Ductal Carcinoma In Situ (DCIS)
Ductal Carcinoma In Situ (DCIS) is a pre-invasive form of
breast cancer.
It is commonly seen in association with an invasive breast
cancer. If it
occurs without an invasive cancer there is usually no lump
associated with
it. On mammography, there may be fine microcalcifications which
can signal
its presence. DCIS is frequently multifocal, meaning it is
located in more
than one area of the breast. Approximately one-third of DCIS
cases are
multifocal. If DCIS is treated with biopsy alone, about 40% of
women will
ultimately develop an invasive cancer of that breast in the
future.
Lobular Carcinoma In Situ (LCIS)
Lobular Carcinoma In Situ (LCIS) is usually encountered as an
incidental
finding in a breast biopsy. It has no symptoms, and has no
characteristic
pattern on mammography. It has been found to occur in multiple
sites in
the same breast in 40 to 90% of cases. In 50% of the cases, it
may also
occur in the opposite breast. The risk of developing an
invasive cancer of
the breast with LCIS is approximately 1% per year. The invasive
cancer
that develops has about an equal chance of being in either
breast
regardless as to which breast the LCIS was initially found. A
large
percentage (38%) of women with LCIS may not develop an invasive
cancer
until more than 20 years after the initial diagnosis.
Inflammatory Carcinoma
Inflammatory carcinoma of the breast is a subtype of
infiltrating ductal
carcinoma, but is named for its typical clinical presentation.
The breast
becomes red, swollen, and warm, and the skin becomes quite
thickened. The
breast appears as if it were infected. This appearance is due
to the rapid
growth of the cancer which blocks the lymphatics in the breast,
causing it
to swell and appear infected. The cancer has already spread to
the lymph
nodes in 90% of the cases at the time of diagnosis. The
prognosis for this
cancer is very poor, and is fortunately relatively uncommon.
Paget's Disease
Paget's disease of the breast accounts for about one to four
percent of
all breast cancers. It occurs typically as a crusting and
scaling of the
nipple. It can be mistaken for a benign skin condition unless
there is a
high index of suspicion.
Cystosarcoma Phyllodes
Cystosarcoma Phyllodes is a firm tumor that resembles a benign fibroadenoma. This cancer is very different than other cancers
of the
breast. It seldom spreads to the lymph nodes, but can
metastasize to other
parts of the body by way of the bloodstream.
For more in-depth information about breast cancer, please read the Breast
Cancer article.
Last Editorial Review: 12/4/2002
