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 type of breast cancer that makes up less than 1% of all invasive breast cancers. It develops when breast cancer cells change their appearance and begin to resemble other cell types, such as flat squamous cells, elongated spindle cells resembling connective tissue, or even cartilage- or bone-like cells. Because of this variety, pathologists describe …
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Invasive breast carcinoma is the most common type of breast cancer. It begins in the cells lining the ducts and lobules of the breast and then spreads through the wall of a duct or lobule into the surrounding breast tissue. The word “invasive” means the cancer cells have broken out of the duct or lobule …
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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 disease of the breast (also written Paget’s disease) is a non-invasive type of breast cancer that involves the nipple and the surrounding skin. It is considered non-invasive because the cancer cells are confined to the skin’s surface layer, the epidermis, and have not invaded deeper tissues. Most cases begin in the milk ducts that …
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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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