I Just Received My Pathology Report – But What Does It Mean?

If you’ve been diagnosed with breast cancer, you know the feeling of being overwhelmed. Your doctor tells you about your pathology report, spitting out terms that you have no clue about. I remember heading straight home to my trusted computer and the internet, pathology report in hand.

My initial diagnosis:

  • Histologic Type: Ductal Carcinoma In Situ
  • Architectural Patterns: Solid, Cribriform, and Focally Comedo
  • Nuclear Grade: Grade III (High)
  • Necrosis: Central (Expansive “Comedo” Necrosis)
  • Primary Tumor: (pT): pTis (DCIS): Ductal Carcinoma In Situ
  • Additional Pathological Findings: Proliferative Fibrocystic Change
  • Ancillary Studies: Estrogen receptor analysis is performed on Ductual Carcinoma In Situ. The results are as follows: Estrogen Receptor (Leica 6F11): Positive (95% of invasive carcinoma nuclei show strong reactivity) by immunohistochemistry.

My second pathology (after my bi-lateral mastectomy) differed from the first, partly because it was a different clinic providing the results. However, I was still floored at the results, despite having a little better knowledge of the terms.

Photo: AdobeStock/WayhomeStudio
Photo: AdobeStock/WayhomeStudio

My Second Diagnosis:

  • Histologic Type: Invasive Lobular Carcinoma grade 2 of 3 (Nottingham combined histologic grade, total score 6/9).
  • Tumor size: Present on two contiguous tissue blocks, largest single dimension is 6 mm
  • Nuclear pleomorphism: Intermediate (2)
  • Mitotic rate: Low (1)
  • Tubule formation: Little (3)
  • Ductal Carcinoma In Situ: No residual DCIS identified.
  • Calcifications: Present in benign breast tissue
  • Estrogen receptor status: Positive (tumor cells staining 90%)
  • Progesterone receptor status: Positive (tumor cells staining 90%)
  • HER2 status: Negative for protein expression by immunohistochemistry (0)
  • Pathologic stage: T1b N0

With all honesty, I was at a complete loss. I thought I had known enough about breast cancer since both my mom and grandma had multiple bouts with the disease, but I was unprepared for these new terms. In fact, it was like learning a foreign language. I was out of my element and needed to know what was growing inside my body, and fast.

Below, you will find a helpful list of terminology frequently used on pathology reports and their meanings.

Photo: AdobeStock/Syda Productions
Photo: AdobeStock/Syda Productions

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Types of Breast Cancer

DCIS – Ductal Carcinoma In Situ: This non-invasive cancer is considered the earliest form of breast cancer. It is the presence of abnormal cells growing in the milk ducts of the breast. “In Situ” means that it has stayed in its original place, not invading other tissue around it.

LCIS – Lobular Carcinoma In Situ (also known as Lobular neoplasia): This is often not considered cancer, but is thought to be a sign that cancer will develop. Here, the abnormal cells start growing in the lobules of the breast, the milk-producing glands.

IDC – Invasive (or Infiltrating) Ductal Carcinoma: 80% of all breast cancers are IDC, making this the most common form of breast cancer. The abnormal cells start developing in the milk ducts, then invades the surrounding tissue.

ILC – Invasive Lobular Carcinoma: Abnormal cells begin developing in the milk-producing tissues. Once it becomes invasive, it spreads to the surrounding tissues.

IBC – Inflammatory breast cancer: This is a rare and aggressive form of breast cancer that occurs in only 1%-5% of all breast cancer cases. Inflammatory breast cancer grows quickly causing redness and swelling of the breast. This is the only form of breast cancer where the treatment decision needs to be made immediately.

Photo: AdobeStock/kei907
Photo: AdobeStock/kei907

Biomarking testing

ER/PR – Your DCIS and invasive cancers will be tested for the hormone receptors: estrogen and progesterone. If it is positive, it means that your cancerous cells have the hormone receptors attached which helps the cancer grow. When found positive, you have more treatment options, such as hormone blockers.

HER2 – Human Epidermal Growth Factor Receptor: This is a gene that controls the growth and repair of cells. If found positive, your cancer will tend to grow faster, spread quicker, and recur in the future.

TNBC – Triple Negative Breast Cancer is found when the cancerous cells tested for estrogen, progesterone, and HER2 come back negative. 10-20% of breast cancers are found to be Triple-Negative, meaning the cancer is not supported by the above receptors.

Photo: AdobeStock/crevis
Photo: AdobeStock/crevis

Type and grading

(The words below describe what the overall tissue looks like under a microscope.)

Cribriform – Cribriform means that there are small holes inside there tumor (think Swiss cheese). It is associated with a quicker growing tumor.

Solid – Solid refers to no holes.

Comedo – This tends to be more aggressive and will plug the center of the breast ducts with necrosis (dead cells).

Necrosis – A lump of dead cells. Necrosis is often seen with calcifications on a mammogram.

*** Tumors can have a combination of all of these. ***

Tubule Formation – This refers to how much of the tumor tissue has normal structures.  Does the duct look like a tube or chaos?

Nuclear Grade – This is an evaluation of the tumor cell which describes how closely the nuclei of cancer cells look compared to those of normal cells in size and shape.

Mitotic Rate – This is a measure of how fast the tumor cells grow and divide.

*** Each of the three above gets a score of 1-3. (Low, intermediate, or high grade) The higher the grade, the more aggressive the tumor can be. ***

Photo: AdobeStock/Konstantin Yuganov
Photo: AdobeStock/Konstantin Yuganov


Stage 0 – This typically is reserved for DCIS and/or LCIS. This stage is non-invasive, pre-cancer, that has not spread into the surrounding tissue.

Stage I – This is an invasive tumor (2 cm or smaller). No lymph nodes are involved in this stage.

Stage II – Typically has a tumor that is 2-5 cm. Lymph nodes may or may not test positive for cancer. Even if the tumor is smaller than 2 cm, yet lymph nodes are involved, the cancer will be considered Stage II.

Stage III – The tumor is larger than 5 cm with involved lymph nodes. The tumor may extend into the skin or pectoral muscles at this stage.

Stage IV – This is where your tumor has spread to other organs, such as your lungs, bone, and brain. This is considered Stage IV no matter the size or number of lymph nodes involved.

The TNM System:

Some pathology results will give you a report with a combination of numbers and letters.

T – Describes the stage of the tumor.

N – Stands for the number of lymph nodes involved.

M – Explains if your cancer has metastasized.

So for example: T1b N0 means Stage 1b with no lymph nodes involved.

Receiving a pathology report can be a daunting experience.  Hopefully this post will help to explain some of the common terminology you may come across.  If you need further clarification, be your own advocate.  Keep asking questions until you are comfortable with the explanations.

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