Understanding Your Pathology Report


“The pathology report is a collection of information that describes a patient’s breast cancer.”

·         How aggressive is the breast cancer?

·         Have any cancer cells left the original tumor and traveled elsewhere, such as the underarm lymph nodes? Are they likely to travel?

·         What determines if my cancer will respond to treatment?

Pathologists are doctors responsible for looking at your tissue sample under the microscope. This allows them to assess the cells for abnormalities that could lead to the diagnosis of breast cancer. They prepare a report about their findings. The report has information about the size, shape and appearance of the cancer as it looks to the naked eye. Pathology reports play an integral role in the diagnosis of breast cancer and staging.

Breast cancer stages are determined by:

·         Tumor size

·         Lymph node status

·         Presence of absence of metastases

What is my breast cancer stage?

A Stage is not always listed in pathology reports because it is derived from the results of the biopsy of the tumor tissue, any biopsies of the lymph nodes and other tests. These biopsies and some pathology tests may not be done at the same time. Thus, you may have more than one report that gives information on staging. Your medical team combines all the pathology information with any scans (to check for spread to other parts of the body) and determines the breast cancer stage.

A complete pathology report will not be ready until you have the definitive surgery to take out all the breast cancer and one or more of the underarm lymph nodes to check for possible signs of cancer there. Over several days to a couple of weeks, this tissue is tested to create that final report. You may even receive a few reports as various tests are done.


This section contains your name, your doctor(s) name, your medical record number and other identifying information. You should always double check that the pathology report has the correct information.

Gross Description

The gross description describes the specimen (tissue sample)  based on what the “naked eye” can see. The pathologist includes things such as the size and weight of the specimen and other observations made by the pathologist. It also describes how the specimen was sectioned and what material were used before the microscopic examination is performed.

What does it mean when my report says carcinoma or adenocarcinoma?

A carcinoma is a cancer that originates in the lining layer (epithelial cells) of organs like the breast. Nearly all breast cancers are carcinomas. Most are the type of carcinoma that starts in glandular tissue called adenocarcinoma.

What does invasive mean?

The normal breast is made of ducts that end in a group of sacs (lobules). Cancer starts in the cells lining the ducts and lobules, when a normal cell becomes a carcinoma cell. Invasive breast cancer is cancer that has broken through the wall (basement membrane) of either a duct or a lobule. The most common form of breast cancer is invasive ductal carcinoma or a cancer that began in a duct and has spread outside the duct. Noninvasive breast cancer is referred to as in situ because it remains in the duct or the lobule. It is considered Stage 0.

What does it mean if my carcinoma is well differentiated, moderately differentiated, or poorly differentiated?

The pathologist looks under the microscope to predict how likely the cancer is to grow and spread. Certain features are able to determine the prognosis of the cancer. Underneath the microscope pathologists look at the cell arrangement.

Well-differentiated carcinomas have relatively normal-looking cells that do not appear to be growing rapidly and are arranged in small tubules for ductal cancer and cords in lobular cancer. These cancers tend to grow and spread slowly and so have a better prognosis (outlook).

Poorly differentiated carcinomas lack normal features, tend to grow and spread faster, and have a worse prognosis. Moderately differentiated carcinomas have features and prognosis in-between these two.

What does Lymphovascular Invasion Mean?

This is the penetration of cancerous cells (often seen as small clusters under the microscope) into the interior of blood vessels and/or lymph channels. Lymphovascular invasion may indicate a more aggressive tumor.

What does grade mean?

Histolopathologic Grade
This measure is often reported using some version of the Bloom-Richardson or the Scarff-Bloom-Richardson scale. It is based on a combined score for nuclear grade, mitotic rate, and histologic grade or architectural differentiation. Each characteristic is given a score of 1 to 3, resulting in a total score ranging from 3 to 9.

Nuclear Grade
Nuclear grade is assessed on a scale of 1-3. A grade 1 (low) indicates small nuclei with little variation in size and shape. A grade 3 (high) indicates larger nuclei with marked variation in size and shape. Grade 2 (intermediate) nuclei show features between 1 and 3. The higher the grade is, the more aggressive the tumor is.

Mitotic Rate
This rate indicates the number of malignant cells that are actively dividing. The mitotic rate is reported with numbers from 1 to 3. The higher the score, the more aggressive the tumor cells are.

Cellular Differentiation
This measure is based on how close the specimen resembles normal breast tissue. This measure refers to tubular formation of the cells. A grade of 1 indicates a well-differentiated tissue with many tubules, grade 2 moderately differentiated, and grade 3 poorly differentiated tissue with few or no tubules.

What hormones make my cancer grow?

Hormone Receptor Status
If your cancer cells have a high proportion of estrogen (ER) or progesterone (PR) receptors, the report will say you are ER positive or PR positive. If your cells have a lower number of receptors, your report will say you are ER or PR negative. Another way to think of this is a car (tumor) and driver (hormones) example. The hormone “buckles” itself into the car seat (receptor) to drive the tumor to make it grow. This is one of the most important pieces of information on the pathology report. Being ER/PR positive means you might benefit from hormonal therapy. Hormone therapy is actually therapy with an oral drug, usually Tamoxifen or aromatase inhibiters, which blocks hormone receptors in the cancer cell.

Type of Biopsy

In a needle biopsy, a needle is used to remove a sample of an abnormal area. An excisional biopsy removes the entire abnormal area, often with some of the surrounding normal tissue. An excisional biopsy is much like a type of breast conserving surgery called a lumpectomy.

What is Her 2 neu?

Her2 positive status is associated with tumors that are fast growing and aggressive. The Her2 gene produces a protein that acts as a receptor on the surface of the cell. This receptor is sensitive to a growth factor, a signal to the cell to grow. If the cancer cells have more receptors than normal, they are receiving more messages to grow and divide.

There are two ways to measure Her2 status. One is an immunohistochemistry (IHC) test, which measures the overexpression of the protein (number of receptors on the surface of the cancer cell) and is reported using the numbers 0 to +3. Scores of 0 and +1 are Her2 negative and +2 and +3 are Her2 positive. If the result is equivocal it may be sent for fluorescent in situ hybridization (FISH), which measures the amplification of the HER-2 gene (the number of copies of the HER-2 gene present in a cancer cell). The results of this test are reported as positive or negative. Only 25% to 30% of women with breast cancer are Her2 positive.

What is Ki-67?

Ki-67 is a direct indicator of the growth of the cancer. It is a cell proliferation associated nuclear antigen and is found in cells in nearly all stages of the cell cycle. It is often reported as a percentage of invasive carcinoma cells exhibiting positive nuclear staining: less than 10% – favorable prognosis, more than 20% – unfavorable diagnosis, 10-20% – borderline category.

The Ki-67 growth fraction is significantly related to the grade in most tumors, being highest in grade III invasive carcinomas. Estrogen and progesterone receptor negative tumors tend to have a high Ki-67 positive fraction, and this index could be used to add adjuvant chemotherapy in both receptor negative and positive patients.


1. www.cancer.org

Posted in: Just Diagnosed, Medical/Science, Staging, Treatment