Understanding Your Pathology Report
The pathology report describes important characteristics of the breast cancer. This information will help you and your doctors choose the best treatments for you and your unique situation.
The term “pathology report” makes it sound like you’ll get just one report with all the information in it. But that’s not what happens. There is more than one type of pathology report.
You’ll receive a report of results each time a test is done. Because not all labs do all tests, you’ll likely receive several different reports. Some tests take longer than others, but most information comes one to two weeks after surgery or a blood draw.
Together, all these reports make up your pathology report. It’s a good idea to keep all
the reports in one place so when you visit your doctors you can discuss any of
Pathologists are doctors who specialize in making a diagnosis by looking at tissue and cells, usually with the help of a microscope. By examining breast tissue and cells, a breast pathologist will issue a report that describes the diagnosis. At this point you may receive a diagnosis of breast cancer. The pathologist may then do more tests on a sample of your blood or cancer tissue removed from your body to further describe the specific type of breast cancer.
There are two main types of pathology reports:
a biopsy pathology report
an excision pathology report with a synoptic summary
The biopsy pathology report describes what is found in the small sample of tissue removed during the biopsy. If the biopsy pathology report finds breast cancer, in most cases you will have surgery to remove the entire cancer, which doctors call an excision.
The synoptic summary in an excision pathology report describes all the characteristics of the whole cancer.
The parts of a biopsy pathology report and an excision pathology report are very similar, with one important difference: the biopsy pathology report will not have information about the stage of the cancer. This is because a cancer’s stage depends primarily on the size of the cancer. Because a biopsy only removes a small piece of the cancer, its size can’t be determined until the whole cancer is removed by excision.
Reading and making sense of all these reports can be scary and confusing. Different labs may use different words to talk about the same things. If there are words in any of the reports that you don’t understand, don’t be afraid to ask your doctor what they mean.
Parts of a pathology report
Different pathologists may use different words to describe the same findings. Pathology reports from different labs may be organized differently. But most pathology reports include these sections:
This part of a pathology report includes your name, birth date, and the date you had surgery or a blood draw. Make sure all this information is correct. This section also may include a number assigned to you to help keep your identity safe.
This section includes the pathologist’s and clinician’s contact information, as well as the lab where the testing was done.
This part of a pathology report includes details about the tissue sample, which doctors call a specimen. This section includes the date the specimen was removed, the type of biopsy or surgery that was done, and the type of tissue it is. In many cases, tissue will be taken from the breast and/or the lymph nodes. If it’s suspected that the cancer has spread (metastasized) to parts of the body away from the breast, tissue may come from other areas, such as the liver or bones.
This section includes information about how the cancer was found and may include other information about your medical history.
This part of a pathology report describes what the pathologist can see with their naked eyes before they look at the removed tissue with a microscope. This usually includes:
the size and weight of the entire specimen
the presence or absence of any masses or lesions and their size, location, relationship to each other, color, and consistency
This section usually is at the front of the pathology report. If cancer has been found, this section summarizes the most important characteristics of the cancer. This part may be long or short, depending on the style of the pathologist.
The final diagnosis usually describes the type of cancer and will likely include information about:
cancer type and grade
hormone receptor status
lymph node involvement
anatomic location (where in the body the cancer is located)
Types of breast cancer you may see in your report include:
DCIS (ductal carcinoma in situ): Non-invasive breast cancer that stays inside the milk ducts. DCIS isn’t life-threatening. But being diagnosed with DCIS increases your risk of being diagnosed with invasive breast cancer in the future.
There are several grades of DCIS:
low-grade (nuclear grade 1)
intermediate grade (nuclear grade 2)
high-grade (nuclear grade 3)
The nuclear grade is an assessment of the size and shape of the nucleus in DCIS cells. DCIS with low nuclear grade grow and spread less quickly than DCIS with high nuclear grade.
The pathology report also may mention the way the DCIS is growing:
papillary: the cells are arranged in a finger-like pattern
cribriform: there are gaps between the cancer cells, like the pattern of holes in Swiss cheese
solid: the cells entirely fill the duct
comedo: there are areas of dead cancer cells built up inside the ducts
LCIS (lobular carcinoma in situ): A collection of abnormal cells that stay inside milk glands or lobules. Even though its name includes the term “carcinoma,” LCIS is considered to be a benign breast condition. For this reason, some experts prefer the term “lobular neoplasia” instead of “lobular carcinoma.” A neoplasia is a collection of abnormal cells. Still, being diagnosed with LCIS increases your risk for developing invasive breast cancer in the future.
Invasive carcinoma: “Invasive” or “infiltrating” means the cancer cells have grown into tissue outside the milk ducts or lobules, and have the potential to metastasize to other parts of the body.
Types of invasive carcinoma:
Invasive ductal carcinoma (IDC): This is the most common type of breast cancer; about 80% of breast cancers are IDC. Several examples of subtypes of IDC are:
Tubular: These cancers are made of tube-shaped structures and look somewhat like healthy breast cells.
Mucinous: These cancers are rare, making up about 2% to 3% of breast cancers. Most of the cancer cells produce mucin, a key ingredient of mucus.
Papillary: This subtype of IDC is very rare, making up less than 2% of breast cancers. Papillary carcinomas are usually diagnosed in older, postmenopausal women. The tumor is made up of small, finger-like projections.
Cribriform: In this type of IDC, the cancer cells invade the connective tissues of the breast as large nests with punched-out holes, which make the tumor look like Swiss cheese.
Invasive lobular carcinoma (ILC): Sometimes called infiltrating lobular carcinoma, this is the second most common type of breast cancer. The cancer cells grow as single, separate cells. In the most typical form, called classic, ILC is made up of small cancer cells that invade the connective tissue of the breast and grow in single-file formation. If the cancer cells grow in a different pattern, the ILC may be classified as one of the following subtypes:
Solid: The cells grow in large sheets with little connective tissue between them.
Alveolar: The cancer cells grow in groups of 20 or more.
Histiocytoid: the cancer cells look like histiocytes or macrophages
Pleomorphic: The cancer cells are much larger than the classic ILC cells.
Signet ring cell: The tumor contains some cells that are filled with mucin and the nucleus is pushed to the side of the cell, giving it a signet ring-like look.
Inflammatory breast cancer: Inflammatory breast cancer is rare — only 1% to 5% of breast cancers are inflammatory. This is a breast cancer that presents with certain clinical features such as swelling and reddening of the breast instead of a distinct lump. This redness and swelling happens because breast cancer cells are blocking lymph vessels in the skin. The skin of the breast also may thicken or dimple, so that it looks and feels like an orange peel. Inflammatory breast cancer tends to grow and spread quickly.
Usually, this diagnosis will be made by your doctor. Still, the pathologist may mention that the cancer cells look like inflammatory breast cancer under the microscope and assign stage pT4d in the synoptic summary.
Paget disease: Also called Paget disease of the nipple, Paget disease of the breast, and mammary Paget disease, this is a rare type of cancer involving the skin of the nipple and the areola, the darker circle of skin around the nipple. About 1% of breast cancers are Paget disease. Most people diagnosed with Paget disease have one or more tumors in the same breast. The cancer cells in Paget disease are usually DCIS, and are staged as pTis. These terms mean that the cancerous cells have not spread beyond the tissue where they began growing.
Phyllodes tumors of the breast: These rare tumors start in the connective tissue, called the stroma, of the breast. About 75% of phyllodes tumors are benign, meaning they are not cancerous. This means that about 25% of phyllodes tumors are cancerous.
There can be two comment sections in a pathology report: one at the end of the final diagnosis and one at the end of the synoptic summary. The comment sections may include more information on tests used or a more detailed explanation of the results.
This is the summary of all the findings about the specimen and the cancer. This part of the pathology report describes in detail what the cells from the sample look like under a microscope and how the cells compare to normal cells. You will have a synoptic summary only if you have had surgery to remove the breast cancer. A synoptic summary is not done for biopsies.
The information in the synoptic summary will repeat some of the information in the final diagnosis section. The synoptic summary is the most technical section of the pathology report. The characteristics of the cancer will help you and your doctor decide on a treatment plan.
Is the cancer invasive or non-invasive?
Non-invasive or in situ breast cancers stay in the place they started to grow. For example, ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS) has not spread beyond the milk ducts or lobules. They don’t grow into the surrounding breast tissue or beyond the breast.
If the breast cancer has grown into tissue outside of the milk ducts or lobules where it began, it’s called invasive or infiltrating. If the breast cancer cells have spread to parts of the body away from the breast, such as the bones or liver, it is called metastatic breast cancer.
In some cases, the tissue removed will have both invasive and non-invasive breast cancer cells. In this case, it’s important to know that treatment will be based on the characteristics of the most aggressive form of cancer — the invasive cancer.
The type of invasive breast cancer will be described in the Final Diagnosis section of the pathology report, either in the biopsy or excision specimen report.
Nottingham grade of the cancer
The Nottingham histologic grade or histologic score describes how the cancer cells look compared to normal, healthy cells in terms of size, shape, and rate of growth. It’s important to know that cancer grade is different from cancer stage.
The Nottingham score is a total of three different scores of the cancer’s characteristics:
tubule formation: how much the tumor looks like normal cell structure
nuclear pleomorphism: how different the tumor cells look from normal cells
mitotic activity: how many cells are dividing
Each characteristic is given a score between 1 and 3, with 1 being the closest to normal and 3 being the most abnormal. The three characteristic scores are added together, giving the Nottingham score. The minimum score is 3 and the maximum score is 9.
There are three cancer grades based on the total score:
Grade 1 (low grade or well-differentiated, score of 3 to 5): Grade 1 cancer cells
look just a little bit different from normal cells.
Grade 2 (moderate grade or moderately differentiated, score of 6 to 7): Grade 2 cancer cells look different than normal cells.
Grade 3 (high grade or poorly differentiated, score of 8 to 9): Grade 3 cancer cells look much, much different than normal cells.
In general, the lower the cancer grade, the better the prognosis, or expected outcome of treatment.
Tumor necrosis means that dead breast cancer cells are in the tissue sample. Tumor necrosis may mean the cancer is more aggressive. This information may be part of either the biopsy or excision pathology report.
Size of the breast cancer
Doctors measure cancers in centimeters (cm) or millimeters (mm). The size of the cancer is very important when determining the stage of the cancer. Size may be given on the biopsy report and is also part of the synoptic summary in the excision pathology report.
When the cancer is removed, the surgeon tries to take out all the cancer, plus a rim of healthy tissue around it, which is called the margin or margin of resection. The pathologist will look to see if there are cancer cells at or in the margin. Positive or involved margins means there are cancer cells at the margin. Negative, clean, or clear margins means there are no cancer cells at the margin. The pathologist also measures the distance between the cancer cells and the margin. Close margins mean cancer cells are close to the edge of the healthy tissue.
This information will only be in the synoptic summary and will not be in a biopsy pathology report.
Lymph is a clear fluid that travels through your body's lymphatic system, helping to rid the body of waste and other unwanted materials. Cancer cells can use the lymphatic system to spread from one location in the body to another very distant location. The pathologist will look at the blood vessels and lymph channels to see if there are cancer cells in them. This is different than having cancer cells in the lymph nodes. If there are cancer cells in the blood vessels, it’s called vascular invasion. If there are cancer cells in the lymph channels, it’s called lymphatic invasion. Usually, lymphatic and vascular invasion are grouped together in the pathology report and called lymphovascular invasion. If there is lymphatic or vascular invasion, your pathology report will say present. If there is no lymphatic or vascular invasion, your pathology report will say absent.
Lymph node status
In most cases at least one or two lymph nodes will be removed during breast cancer surgery. The pathologist will look to see if there are cancer cells in those lymph nodes.
Lymph nodes are the filters along the lymphatic system. Their job is to filter out and trap bacteria, viruses, cancer cells, and other unwanted substances, and to make sure they are safely eliminated from the body.
If there are cancer cells in the lymph nodes, there is a higher risk that the cancer has spread to other places in the body. If there are cancer cells in the lymph nodes, the report will say positive. If there are no cancer cells in the lymph nodes, the report will say negative or benign. The pathologist also will say how many lymph nodes have cancer cells in them, as well as how many cancer cells are in each node.
In some cases, the pathologist may use the words below to describe how many cancer cells are in each lymph node and where there are in relation to the lymph node structure:
Isolated tumor cells: Fewer than 200 cancer cells are in the lymph node, or the cancer in the lymph node is 0.2 mm or smaller in size.
Micrometastasis: There are 200 cancer cells or more in the lymph node, or the cancer in the lymph node is between 0.2 mm and 2 mm in size.
Macrometastasis: The cancer in the lymph node is larger than 2 mm.
Extracapsular extension: The cancer has spread outside the wall of the lymph node.
Unless the pathologist evaluated a biopsy of a lymph node, this information will only be in the synoptic summary and will not be in a biopsy pathology report.
If you had treatment before surgery to remove the cancer, which doctors call neoadjuvant treatment, your report will have this section. It usually includes:
Tumor bed size: The overall size of any remaining cancer found during surgery after neoadjuvant treatment.
Tumor bed cellularity: The percentage of cancer cells found in the tumor bed.
If no cancer is found after neoadjuvant treatment, the pathologist will say no residual carcinoma.
This information will only be in the synoptic summary and will not be in a biopsy pathology report.
Hormone receptor status
The invasive breast cancer will be tested to see if the cancer cells have receptors for the hormones estrogen and progesterone.
A cancer is called estrogen receptor-positive (ER-positive) if it has estrogen receptors. A cancer is called progesterone receptor-positive (PR-positive) if it has progesterone receptors.
Breast cancers may be both ER-positive and PR-positive.
In many cases, doctors use the term hormone receptor-positive (HR+) for cancers that are estrogen receptor-positive, progesterone receptor-positive, or both.
If the cancer has no estrogen or progesterone receptors, it’s called hormone receptor-negative (HR-).
Learn more at Hormone Receptor Status.
This information will only be in the synoptic summary and will not be in a biopsy pathology report.
The HER2 gene makes HER2 proteins, which are sometimes called HER2/neu proteins. HER2 proteins are receptors on breast cells. Normally, HER2 receptors help control how a healthy breast cell grows, divides, and repairs itself. But in about 10% to 20% of breast cancers, the HER2 gene doesn’t work right and makes too many copies of itself; doctors call this HER2 gene amplification. All these extra HER2 genes tell breast cells to make too many HER2 proteins, which is called HER2 protein overexpression. This makes breast cells grow and divide in an uncontrolled way.
Breast cancers with too many HER2 genes are called HER2-positive.
Learn more at HER2 Status.
Breast cancer stage
Breast cancer staging can be pathologic or clinical.
The pathologic stage of a breast cancer is determined by the pathologist and is labeled with the prefix “p.” The pTNM stage is determined by the cancer’s characteristics, most importantly by how large it is and whether cancer cells are in the lymph nodes. The purpose of the staging system is to help guide treatment decisions and provide a common way to describe breast cancer so treatment results can be compared.
The T, N, and M letters in the staging system stand for:
the size of the cancer tumor and whether it is invasive (T) or non-invasive (Tis)
whether cancer is in the lymph nodes (N)
whether the cancer has spread to other parts of the body beyond the breast (metastasized) (M)
Numbers or letters after T, N, and M give more details about each characteristic. Higher numbers mean the cancer is more advanced.
If you have treatment before surgery to remove the breast cancer, which doctors call neoadjuvant treatment, then the stage is determined after treatment and is reported as ypTNM. The “y” stands for “after treatment.”
Clinical staging is based on the results of any tests done before surgery, such as an exam by your doctor or mammogram or MRI results. Clinical stage is determined by your oncologist and is labeled with the prefix “c” before TNM. Clinical staging information is not included in the pathology report.
Your doctor uses the pathologic stage information to determine a clinical stage to help make treatment decisions.
You may hear the terms early-stage and advanced-stage. These are clinical staging terms, not pathologic staging terms, so probably won’t be in your pathology report. Still, because these terms are commonly used, we’ve included them here.
Learn more at Breast Cancer Stages.
The tests listed below are extra tests that are not recommended for everyone suspected of having breast cancer, and the results are not part of the synoptic summary. You may or may not have these results.
Rate of cell growth
The pathologist may do other tests to see how quickly the cancer cells are dividing, which also is called the mitotic rate. Cancers that are slow growing are usually low-grade and cancers that are growing quickly are usually high-grade.
One way of measuring how quickly the cancer cells are growing is a special stain called Ki-67. Still, right now, Ki-67 testing is not a recommended routine test because the results can vary widely and may not always be completely accurate.
The ploidy of cancer cells refers to the amount of DNA they contain. If most of the cancer cells have a normal amount of DNA, they’re called diploid. These cancers tend to grow and spread more slowly. If the amount of DNA is abnormal, the cells are called aneuploid. These cancers tend to grow and spread faster. Still, tests of ploidy rarely change breast cancer treatment and are considered optional.
Genomic tests, also called tumor genomic assays, analyze the cancer to see how active certain genes are. Different genomic tests analyze different sets of genes. The activity level of these genes affects the behavior of the cancer, including how likely it is to grow and come back after treatment. Genomic tests are used to help make decisions about whether treatments after surgery, such as chemotherapy, would be beneficial.
While their names sound similar, genomic testing and genetic testing are very different.
Genetic testing usually is done on a sample of your blood or saliva and looks for an abnormal change, called a mutation, in a gene linked to a higher risk of breast cancer.
Genomic testing looks at certain genes in cancer cells to see how active they are.
Learn more at Screening and Testing.
Cells are the building blocks of every living thing. Genes in the center of a cell tell the cell what to do. Genes are made of DNA (deoxyribonucleic acid). Changes in genes, called abnormalities or mutations, can tell a cell to make — or not make — certain proteins that affect how a cell grows and divides. Certain mutations can cause cells to grow out of control, which can lead to cancer.
Three of the most well-known genes that can mutate and raise the risk of breast and ovarian cancer are BRCA1, BRCA2, and PALB2. Women who inherit a mutation, or abnormal change, in any of these genes — from their mothers or their fathers — have a much higher-than-average risk of developing breast cancer and/or ovarian cancer. (Abnormal PALB2 genes are suspected to raise the risk of ovarian cancer, but larger studies need to confirm that risk.) Men with these mutations have an increased risk of breast cancer, especially if the BRCA2 gene is affected, and possibly of prostate cancer. Many inherited cases of breast cancer have been associated with mutations in these three genes.
Genetic testing looks for mutations in a person’s genes. Testing for genetic mutations linked to breast cancer is usually done on a blood or saliva sample taken in your doctor’s office and sent to a commercial lab or research testing facility. Genetic tests can look at one entire gene for a mutation or they can look at a set of genes to see if there are mutations. Genetic tests that look at multiple genes are called panel tests and can include as few as 2 genes or as many as 30 or more genes.
Learn more at Genetic Testing.
Broad molecular profiling tests
Broad molecular profiling tests look at all the genes in a cancer tumor — called the genome — to see if there are mutations that have accumulated over time.
Other names for broad molecular profiling include:
comprehensive genomic profiling
Broad molecular profiling is different from genomic testing because it looks at the entire genome of the cancer. Genomic tests only look at a particular set of genes that affect how likely the cancer is to come back.
There are two types of genetic mutations:
Inherited genetic mutations are passed down from parent to child, such as an inherited BRCA1 or BRCA2 mutation. Inherited mutations are called germ-line mutations.
Somatic genetic mutations happen over the course of a lifetime, as a result of the natural aging process or exposure to chemicals in the environment.
Genetic testing is used to find germ-line mutations.
Broad molecular profiling tests are used to find somatic mutations in the cancer tumor.
Learn more at Broad Molecular Profiling Tests.
If you have been diagnosed with certain types of breast cancer that is hormone receptor-negative and HER2-negative (triple-negative), PD-L1 testing may be done on the breast cancer to see if an immunotherapy medicine such as Keytruda (chemical name: pembrolizumab) may help treat it.
Keytruda is an immune checkpoint inhibitor medicine. Immune checkpoints are proteins in your body that help your immune system tell the difference between your own cells and foreign invaders, such as harmful bacteria. Cancer cells sometimes find ways to use these immune checkpoint proteins as a shield to avoid being identified and attacked by the immune system.
Immune checkpoint inhibitors target these immune checkpoint proteins and help the immune system recognize and attack cancer cells. PD-1 is a type of checkpoint protein found on T cells, which are immune system cells that roam throughout the body looking for signs of disease or infection. PD-L1 is another checkpoint protein found on many healthy cells in the body. When PD-1 binds to PD-L1, it stops T cells from killing a cell.
Still, some cancer cells have a lot of PD-L1 on their surface, which stops T cells from killing these cancer cells. An immune checkpoint inhibitor medicine that stops PD-1 from binding to PD-L1 allows T cells to attack the cancer cells.
The PD-L1 immunohistochemical (IHC) test uses a chemical dye that stains the PD-L1 proteins on the cancer cells. In tests measuring PD-L1 clone SP142 proteins, if 1% or more of the cancer cells are stained, the cancer is considered PD-L1 positive and may be able to be treated with Keytruda. If the test measures PD-L1 clone 22C3 proteins, 10% or more stained cancer cells means the cancer is considered PD-L1 positive.
What does prognosis mean?
Prognosis means the expected outcome of breast cancer treatment. Prognosis isn’t part of the pathology report, but your doctor uses all the information in the pathology report to determine your prognosis, so we’ve included it here.
Doctors often use survival rates to talk about your prognosis. While some people want to know the statistics for others in similar situations, it’s important to remember that each person and each breast cancer is unique. Survival rates usually are based on the outcomes of many, many people diagnosed with breast cancer, but survival rates can’t predict what will happen in your particular situation.
Think about whether you want to know about breast cancer survival statistics before you read beyond this point.
The five-year survival rate is the percentage of people who live at least five years after being diagnosed with breast cancer. Many people live much longer than five years after being diagnosed. It’s also important to remember that people diagnosed with breast cancer can die from other causes — stroke or heart attack, for example. The five-year survival numbers don’t take into account that some people died from something other than breast cancer.
To get five-year survival rates, doctors look at people who were diagnosed and treated at least five years ago. Sometimes researchers estimate five-year survival rates based on information from shorter periods of follow-up. Survival rates can be given in other periods of time besides five years — 10 years, for example.
The American Cancer Society publishes five-year survival rates for people diagnosed with breast cancer using numbers from the Surveillance Epidemiology and End Results (SEER) database from the National Cancer Institute. The SEER database doesn’t group cancers by clinical stage (stage I, stage II, etc.). Instead, it classifies cancers as:
localized: there is no sign the cancer has spread outside the breast
regional: the cancer has spread outside the breast to nearby tissues or lymph nodes
distant: the cancer has spread to parts of the body away from the breast, such as the lungs, liver, or bones
The five-year survival rates below are based on women diagnosed with breast cancer between 2010 and 2016:
all SEER stages combined: 90%
The five-year survival rates below are based on men diagnosed with breast cancer between 2010 and 2016:
all SEER stages combined: 84%
It’s important to know several things about these statistics:
People now being diagnosed with breast cancer may have a better outlook than these numbers suggest, as many new treatments have been developed since 2010.
The numbers apply only to the stage of the cancer when it was first diagnosed. They do not apply to cancer that spreads or comes back after treatment.
The Understanding Your Pathology Report booklet
— Last updated on August 10, 2022, 3:26 PM