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General Surgery

Your Pathology Report

What does the pathology report mean?

A pathology report is a medical document of his/her findings summarized by a pathologist. A pathologist is a doctor who is specialized in examination of body cells and tissues and aid in the diagnosis of a disease. Pathology reports are written in technical medical language.

Samples of breast tissue and lymph nodes removed during the biopsy will be sent to a pathologist for examination. This process may take several days or more.

What information does a pathology report include?

A pathology report may include some details about the patient, clinical diagnosis, the procedure, macroscopic description (description of how the specimen appear to the naked eye), microscopic description (description of the how the tissue looks under the microscope), and a pathologic diagnosis.

The structure of your pathology report is as follows:

  • Your name, date of birth and contact number, referring doctor’s name, and the date/type of surgery performed.
  • Description of the breast tissue before it looked at under a microscope known as macroscopic description. This section of the report includes size, weight and appearance of the tissue, original location in the breast, and the preparation of the tissue for the microscope.
  • Microscopic description of the tissue represents the typical features of the cancer under a microscope. These include the type and status of cell, tumor size and grade.

Breast cancer pathology report is one of the most complex pathology reports.

Type of Breast Cancer:

The normal breast tissue is composed of lobules, that produce milk and ducts (passage) which carry the milk to the nipple. Breast cancer starts in a lobule or a duct; depending upon the type of breast cancer, the treatment plan is framed. The cancer can be non-invasive (does not spread beyond the lobule/duct) or invasive (spreads beyond the lobule/duct) in nature.

Types of Non-Invasive Breast Cancer:

  • Ductal Carcinoma In Situ (DCIS): This is the most common type of non-invasive breast cancer, also known as intraductal carcinoma. It is malignant in nature and as the tumor progresses; the nucleus of the tumor loses its vitality. This calcified area of necrosis is detected on a mammogram. DCIS tumors are further recognized by how the cells appear under the microscope and divided into different subtypes: comedo, papillary, micropapillary, solid and cribiform. DCIS is described as low, intermediate or high grade.
  • Lobular Carcinoma in Situ (LCIS): LCIS is an accumulation of abnormal cells in the lobule. . Unlike other lesions, these lesions rarely develop necrosis or calcifications and unidentified on a mammogram. It strongly poses as a risk factor for development of breast cancer. The pathologist incidentally detects LCIS in a biopsied tissue sample.

Types of Invasive Breast Cancers:

  • Infiltrating Ductal Carcinoma (IDC): This type of invasive tumor begins in the duct and spreads beyond the duct into the surrounding normal breast tissue. IDC is common and accounts for about 85% of reported cancer cases.
  • Infiltrating Lobular Carcinoma (ILC): ILC is a rare tumor that starts in the lobule and extends beyond the lobule into normal tissue.
  • Medullary Carcinoma: These cancers typically have a well-defined boundary between the cancer cells and the normal cells. Medullary carcinoma accounts for only 5-10% of all breast cancers cases in women.
  • Tubular Carcinoma: Tubular carcinoma is a rare type of invasive breast cancer, accounting for about 2% of breast cancer cases. The microscopic picture presents as a tubular pattern in most of the cases. The cancer does not metastasize and is associated with a very good prognosis.
  • Mucinous Carcinoma: Mucinous carcinoma is an unusual type of slow growing breast cancer. The tumor cells produce a substance known as mucin (protein and sugar compound). These tumors also rarely metastasize and are associated with a good prognosis.

Other Rare Subtypes:

  • Metaplastic – A rare variation of IDC
  • Adenoid Cystic – Rare variation of a tumor that more commonly occurs in the salivary gland
  • Papillary
  • Paget’s disease of the breast is characterized by red, crusty lesion on the nipple and surrounding breast tissue. It is a rare breast condition that is often associated with an underlying breast cancer.

Histological Grade:

Histological grade is reported by means of “Bloom Richardson Scale” or “Nottingham Score”. It is a combination of nuclear grade, mitotic rate, and tubule formation, which are characteristics of the tumor cells seen under a microscope that reflect/predict its aggressiveness. Rate of recurrence is high among the high grade tumors when compared to low grade tumors.

  • Nuclear Grade: A score is given from 1 to 3, based on the appearance of the nucleus of the cancer cells, with 1 being the closest to normal cells (better), 3 being the most variation (worse)
  • Mitotic Rate: Describes how quickly the cancer cells are multiplying or dividing using a 1 to 3 scale, 1 being the slowest, 3 the most rapid
  • Tubule formation: This score represents the percent of cancer cells that are in tubule formation. A score of 1 means greater than 75% of cells are in tubule

formation (better), a score of 3 is used when less than 10% of cells are in tubule formation (worse), a score of 2 is in between 10 and 75%
The three scores are then combined for a total score between 3 (1+1+1) and 9 (3+3+3). This score interprets a histological grade. The following is a presentation of histological grade:

  • Score of 3, 4 or 5: Well differentiated or low grade (Grade 1)
  • Score of 6 or 7: Moderately differentiated or intermediate grade (Grade 2)
  • Score of 8 or 9: Poorly differentiated or high grade (Grade 3)

Tumor Size:

The size of the tumor is measured in centimeters and the location depends on the quadrant in which it is found: assume the breast is divided into 4 quadrants – upper inner quadrant (UIQ), upper outer quadrant (UOQ), lower outer quadrant (LOQ), and lower inner quadrant (LIQ).

Multi-centric means there is more than one area of breast cancer in different quadrants of the breast. Multi-focal means more than one area has been noticed but only in one quadrant of the breast.


Margins are the edges of the excised surgical specimen that gives an indication of how close the cancer comes to the edge. A “clean” or “clear” margin is defined as no tumor cells within 1-2 millimeters of the edge of the specimen. If the tumor cells are closer than this to the margin, additional surgery may be needed.

The pathologist examines the tumor and surrounding tissue to detect any tumor cells has invaded them.

Lymph Nodes:

The lymph system is a network of lymph nodes, lymph ducts, and lymph vessels. The lymph nodes contain cells that act as a filter to clear bacteria and dead tissues from the body. Lymph is a fluid that flows between cells in the body and functions to clear the foreign debris.

Cancer cells enter the lymphatic system and spread to other parts of the body. During breast cancer surgery, lymph nodes are removed and checked for the presence of cancer cells.

Hormone Receptor Status:

Hormone receptor status is a main factor in planning breast cancer treatment. Some breast cancer cells grow with the help of estrogen and/or progesterone. These cancer cells have hormone receptors on them and when the hormone attaches to the receptor, it allows the cell to grow and multiply.

A pathologist determines the hormone receptor status by testing the tumor tissue removed during a biopsy.

  • Hormone receptor-positive breast cancers have many hormone receptors
  • Hormone receptor-negative breast cancers have few or no hormone receptors.

Hormone therapy helps to slow or stop the growth of breast cancer cells by lowering the level of estrogen in the body or by blocking estrogen from attaching to the receptors.

HER2 (Human Epidermal growth factor Receptor 2) Status:

The HER2 is a gene that stimulates production of HER2 proteins (receptors) found on the surface of breast cells that help control the cells to grow and divide. In about 25% of breast cancers, there are too many copies of the gene or the protein is over expressed on the cell surface, causing the cancer to grow faster and be more destructive. Breast tumors are routinely tested to see if they have too many copies of the gene or over express the protein.

Following are the tests for HER2:

  • Immunohistochemistry (IHC) test: This test looks for over expression of the protein and is reported as a number from 0 to +3. Zero and +1 are considered Her 2 negative, +2 is borderline and +3 is considered HER2 positive.
  • CISH (chromogenic in situ hybridization) and FISH (fluorescent in situ hybridization): These tests examine the tumor for extra copies of the HER2 gene and are reported as positive or negative. These are regarded as the definitive tests on which the final decision regarding treatment will be made.

HER2 positive tumors may be treated with medication called Herceptin. Herceptin attaches itself to the HER2 receptors on the breast cells and blocks them from receiving growth signals. Thus, it helps to slow or even stop the growth of breast cancer cells.

Talk to your breast care team if you have concerns regarding your pathology report.