Breast fat necrosis is a benign or non-cancerous condition that occurs as an after-effect of surgery or radiation. Although far less common, it also can develop in response to an injury to the breast. It can be concerning for women because it often presents as a lump or mass that warrants further medical investigation. Fat necrosis can be difficult to distinguish from a carcinoma of the breast on a mammogram.
Necrosis literally means death of living cells, usually occurring in a localized area. Breast fat necrosis therefore forms when the blood supply to the fat lobules is compromised, usually the result of trauma to the area. When these cells don't receive adequate oxygenated blood, they die. Your body then tries to rid itself of these dead cells by releasing enzymes to break them up. Sometimes scar tissue forms in the area where the cells have died. The cells also can release fat and form a sac of greasy fluid referred to as an oil cyst. Both of these can lead to the formation of a lump or mass. These lumps are normally painless and are more common in obese, middle-aged women who have larger breasts.
Breast fat necrosis was first cited in a 1920 study presented to the American Surgical Society. Authors Lee and Adair discussed several cases where women underwent a mastectomy for the removal of a suspicious mass, which later proved to be a benign area of fat necrosis. The authors hoped that by identifying this new condition and highlighting how it often presents like a carcinoma of the breast, they would save women needless surgery, particularly the radical mastectomy and possible post-operative complications.
According to a study by Dvora Cyrlak published in the 1999 journal of RadioGraphics, the most common cause of breast fat necrosis is surgery, whether it be a biopsy in the breast area, lumpectomy, mastectomy, a breast reduction, implant removal, breast reconstruction or in some cases, radiation therapy. Another possible cause is injury to the breast, such as a blunt chest trauma or a seat belt injury. Lori Santoro, a nurse educator at CancerCare Manitoba's Breast Cancer Center of Hope, said the fat necrosis she is most familiar with is post-breast reconstruction surgery after a mastectomy. Part of the reconstructed tissue can have a compromised blood supply leading to some tissue death, Santoro says. When this happens, she encourages women to gently massage the area. In some cases, the plastic surgeon has to go back in and remove the area of necrosis if it becomes bothersome. Generally speaking, however, there are no specific treatment recommendations for fat necrosis. Some doctors advise patients to apply a cold compress to the area, but the lumps often resolve on their own.
Because an area of fat necrosis can often mimic a carcinoma of the breast on a mammogram, your doctor may recommend an ultrasound, MRI or even a needle biopsy to rule out cancer. If there is scar tissue in the area where the fat cells have died, the borders of the tissue can look thick and irregular, the shape and characteristic of some breast cancers. An experienced radiologist can usually recognize the subtle differences between the two. Never self-diagnose a lump you may find in your breast or assume because you've had an injury to the area it's fat necrosis. Always consult your doctor when you find a lump of any kind in your breast.