Your Pathology

If a lump or area of concern is found on a mammogram, a sample of tissue is removed (or biopsied) from the suspicious mass or lesion for microscopic examination. The biopsy is then sent to a lab where a pathologist (a specialist in diagnosing diseased tissue specimens) analyzes it and prepares a pathology report. The report indicates if the tissue is benign or malignant.  If a malignancy is diagnosed, the pathology report provides the surgeon and oncologist with the information they will need to develop a treatment plan.

There are many different types of cells located in the breast. Each has its own unique characteristics therefore if cells become cancerous, each is treated quite differently (see ‘Types of Breast Cancer’). A biopsy pathology report will describe the type of cancer, the grading of the tumour, and perhaps the size of the tumour and margins. A surgical pathology will describe these same things but also include information about node status if lymph nodes were sampled.

Margins are the area of tissue surrounding a tumour. If the surgical surface of the surrounding tissue has no evidence of cancer, the report will state the tissue margins are “clear”.  When clear margins are not obtained, the potential for local disease recurrence is increased. 

Node status describes how many lymph nodes were removed and how many tested positive for cancer.

Normal ducts and lobules are lined with one or two layers of cells that are in an orderly pattern. In situ cancers are cancer cells which develop and grow but do not break through the walls (also called the basement membrane) and remain in the duct or lobule where it began (good prognosis). Invasive cancers are cancers of the ducts or lobules which have broken through the wall and has began to grow into the surrounding tissue. If breast cancer has spread it is common for it to go into the lymph system to the lymph nodes.  

Grading and staging of cancer describe how aggressive the tumour is and how far it has spread (Additional information on grading and staging is found on additional pages on this website).