The estrogen receptor (ER) and progesterone receptor (PR) are proteins found inside breast cancer cells that respond to the hormones estrogen and progesterone. When a breast cancer test is positive for these receptors, it means the cancer cells are using hormones as fuel to grow. This information is one of the most important results on …
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A fibroepithelial lesion is a term pathologists use to describe a group of breast tumors that contain both epithelial cells (cells that line breast ducts) and stromal cells (the connective tissue that supports the ducts). This is not a final diagnosis. Instead, it is used when the tissue sample from a biopsy is too small …
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Triple-negative breast cancer is a term used to describe breast cancers that do not show expression of three common markers: Estrogen receptor (ER). Progesterone receptor (PR). HER2 (also called ERBB2). These three markers are important because they are often used to guide treatment. Breast cancers that are ER-positive, PR-positive, or HER2-positive can be treated with …
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Metaplastic carcinoma is a rare and aggressive type of breast cancer. It develops when cancer cells from the breast change their appearance and begin to resemble other types of cells. For example, the tumour may contain: Squamous cells (flat cells normally found on the surface of the skin and lining surfaces of the body). Spindle-shaped …
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Invasive breast carcinoma (not otherwise specified) is the most common type of breast cancer. It starts in the cells lining the ducts of the breast and invades surrounding breast tissue. This type of cancer is often referred to as invasive ductal carcinoma. It is the most common form of breast cancer. The diagnosis of invasive …
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Encapsulated papillary carcinoma is a rare and distinct type of breast cancer that is usually non-invasive. Non-invasive means the cancer cells have not spread beyond their original location into the surrounding breast tissue. The tumor grows inside a small, cyst-like space and is surrounded by a thick fibrous capsule — a layer of connective tissue …
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Paget’s disease is a non-invasive type of breast cancer that involves the nipple and surrounding skin. It is considered non-invasive because the tumour cells are limited to a layer of the skin called the epidermis. Most tumours are believed to start in channels called ducts that run from the nipple to glands deep in the breast. …
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Sclerosing adenosis is a non-cancerous growth made up of small glands in the breast. The glands are surrounded by a type of connective tissue that resembles a scar. When large enough, this type of growth can be seen in imaging studies such as mammography, and a biopsy may be performed to rule out cancer. What …
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Pseudoangiomatous stromal hyperplasia (PASH) is a non-cancerous growth in the breast. It is made up of specialized cells called myofibroblasts. The growth is called “pseudoangiomatous” (which means “like blood vessels”) because the myofibroblasts form small slit-like spaces that look similar to blood vessels when examined under the microscope. What causes PASH? PASH appears to be …
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The Nottingham histologic grade (or modified Scarff-Bloom-Richardson grade) is a system pathologists use to evaluate breast cancer under the microscope. It helps determine the aggressiveness of the cancer and provides important information for planning treatment. The grade is based on how different the cancer cells look from normal breast cells and how quickly they are …
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