Characteristics of Breast Cancer Lumps

Breast cancer develops from abnormal and dysregulated growth of cells in the breast, which occurs due to the accumulation of genetic mutations within a small population of cells. These cells become immortal and divide indefinitely, giving rise to a tumor. There are a range of forms of breast cancer, which differ in where they originate and their severity. Often a cancer will present as a breast lump, and the characteristics of the lump help define the type of breast cancer, and guide future treatment strategies.

An artist rendering of a lump in a woman's breast. (Image: xrender/iStock/Getty Images)


A breast cancer lump consists of a number of very closely-packed cells dividing out of control. In some forms of breast cancer, the lump will often be surrounded by scar tissue that develops as a result of tissue damage from the tumor. This type of breast cancer lump will often feel very firm and hard to the touch.

Other forms of cancer may present as a lump that feels like a thickening of breast tissue. The University of Cincinnati reports that certain types of breast carcinoma lumps will often contain smaller projections, so the breast lumps will feel flatter and less noticeable.


Breast cancer lumps are characterized by where they occur within the breast. Breast cancer lumps most commonly occur within the ducts of the breast, the tubes that connect the milk-secreting lobules to the nipple. Cancer lumps originating in the ducts are called ductal carcinomas. Breast cancer lumps can also develop within the lobules, which is called lobular carcinoma.

The University of Maryland Medical Center reports that the physical location of the tumor within the breast also helps characterize a breast cancer lump. Breast lumps can occur deep within the breast, near the skin, as well as near the edges of the breast, under the arm or behind the nipple. The University of Maryland states that cancer lumps located in the middle of the breast often prove more serious than those to develop to the sides of the breast.


Breast cancer lumps may be characterized by whether the patient experiences pain in their breast. Lumps within the breast that become painful and tender to the touch often prove non-cancerous, and may instead indicate benign tumors or other growths. Breast cancer lumps generally don not feel painful to the touch, although a lack of pain alone is not sufficient to rule out the possibility that a breast lump results from cancer.

San Diego State University reports that around 15 percent of women with breast cancer suffer from breast pain as a result of the lump. Pain associated with a breast cancer lump is usually only affects one breast, and presents as a persistent pain that is localized around the lump. Further testing of a painful breast lump can diagnose or rule out the possibility of cancer.

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