Breasts fat necrosis is a benign (noncancerous) condition that can occur from injury to the breast tissue or medical procedures. This condition can cause lumps that feel like breast cancer and look like tumors on a mammogram.

These lumps can occur at any age and appear anywhere in the breast, but they’re more common in women who are obese or have very large breasts.

This article will outline some of the causes of breast fat necrosis, the procedures used to diagnose it, and how to treat it.

Necrosis is a medical term used to describe damaged or dead tissue.

Symptoms

Fat necrosis develops when the body replaces damaged cells with firm scar tissue.

The effects can include:

  • Lumps: A lump may feel hard and round or like a section of thick skin. Sometimes the fat cells turn into scar tissue or form a sac-like collection of oily fluid called an oil cyst, which may feel like a smooth and squishy lump (akin to a small grape).
  • Pain: This condition usually is painless, but your breast may feel tender or painful in the area surrounding the necrosis.
  • Changed appearance: The skin around the lump may look red and bruised. You may see some drainage from the nipple that’s nearest the bruised region. The nipple may pull inward a little bit, or the breast skin may dimple above the lump of fat necrosis.

Characteristics of fat necrosis include:

  • The lumps are often periareolar (around the areola, which is outside the nipple) and superficial (felt just under the skin).Bruising or tendernessSkin tethering or dimplingNipple retraction

The symptoms of breast necrosis can be the same as symptoms of breast cancer. It is important to seek medical care to determine the cause of your symptoms.

Causes

There are a few causes of fat necrosis. The most common cause is trauma, followed by surgery with postoperative radiation therapy, which happens in 4%–25% of people.

After the area of breast fat necrosis appears, it may increase in size, decrease in size, or stay the same. It may persist for years or may resolve, leaving behind fibrosis and calcifications that may be seen on a mammogram.

Injury

Fatty breast tissue can become damaged after any type of traumatic breast injury, for instance being hit by a ball or restrained by a seatbelt or airbag during a car accident. Sometimes, though, fat necrosis develops without any trauma.

Radiation Treatment

The use of ionizing radiation to treat cancer cells may sometimes cause an area of fat necrosis that can be mistaken for a breast cancer recurrence. This appears to be more common in people who have accelerated partial radiation—a type of radiation given only to the part of the breast that has cancer in it.

Breast Surgery

Any type of breast surgery can damage the fatty tissue, including biopsies (such as a needle biopsy or surgical biopsy to remove sample tissue to be tested in a lab), reconstruction, reduction, and lipomodelling (or fat transfer), which is when fat is taken from another part of the body and injected into the breast.

Fat necrosis is more common in those who have breast cancer surgery and also receive adjuvant chemotherapy, which is given to prevent recurrence of the original tumor. The condition is becoming more of a concern with fat grafting during reconstruction since it can be difficult to differentiate fat necrosis from a breast cancer recurrence.

Diagnosis

Fat necrosis can be difficult to diagnose because it often looks and feels like many other types of breast lumps. Both during a clinical breast exam and a mammogram, ultrasound, or magnetic resonance imaging (MRI), the mass may look like a malignant breast tumor—dense, with an irregular shape, a spiky border, and a collection of microcalcifications (tiny calcium deposits). MRI can detect the amount of the inflammatory reaction, the amount of liquefied fat, and the degree of fibrosis. 

Fat necrosis in the breast may appear to be atypical lipoma or liposarcoma, types of tumors that are very rarely found in breast tissue. If the fat has turned into liquid, it can look like a cyst on an ultrasound.

To diagnose fat necrosis, a biopsy is often needed.

Fat necrosis can take on different appearances over time, so follow-up mammograms will show a change in the mass.

Oil cysts are usually diagnosed with needle aspiration, a type of biopsy procedure in which a sample of the fluid is removed from the mass via a thin, hollow needle and then microscopically examined.

Treatment

According to the American Cancer Society, fat necrosis and oil cysts usually don’t need to be treated. Sometimes fat necrosis goes away on its own, as the body breaks it down over time.

If you’ve recently had a breast injury or surgery and you suspect fat necrosis, try warm compresses and gentle massage. With care, the tissue may heal.

When fat necrosis causes pain, you can take Advil or Motrin (ibuprofen) or aspirin. For severe pain, ask your healthcare provider about prescription pain medicine.

In cases in which the mass is large and causing significant discomfort or distress, it may be removed with a vacuum-assisted core-needle biopsy or a lumpectomy (surgery to remove cancerous or abnormal tissue from the breast). If a needle aspiration is done to remove the fluid in an oil cyst, it can also serve as treatment. Oil cysts can also be surgically removed.

Even if your symptoms go away, be sure to mention them—and any other changes in your breast—to your healthcare provider.

Prevention

Benign breast conditions like fat necrosis often develop without an explanation, so they can’t really be prevented. But you can reduce the risk of getting them. One study has shown that low-dose nitroglycerin ointment applied to the skin significantly decreased the rate of necrosis in patients who underwent breast reconstruction after skin-sparing or nipple-sparing mastectomy.

Summary

Breast fat necrosis is a benign condition that can occur from trauma or surgical procedures such as breast augmentation or breast cancer surgery. It doesn’t increase a person’s risk for breast cancer. A clinical exam and mammogram are tools used to diagnosis this condition and follow-up surgery may be used to remove them.

A Word From Verywell

Fat necrosis can be frightening for women and a challenge for healthcare providers. That said, through a combination of imaging studies and a biopsy, if needed, you and your healthcare provider can be sure the changes you’re experiencing are remnants of past damage to your breast tissue and nothing more.

Frequently Asked Questions

  • How common is breast fat necrosis?
  • Fat necrosis is found in 0.8% of breast tumors and in 1% of women who undergo breast reduction surgery.
  • Can fat necrosis be mistaken for breast cancer?
  • Yes, it can. Breast fat necrosis is a benign (noncancerous) condition, but the lumps can feel like cancer tumors. A clinical exam and mammogram can differentiate between cancerous and noncancerous tumors.
  • Does breast fat necrosis go away?
  • Yes, the condition may go away on its own. If it doesn’t, you may need to have it surgically removed. One option for removal is liposuction and another is a lumpectomy.
  • Can breast fat necrosis grow?
  • Yes, it can grow in different parts of the breast. It can also shrink.

Fat necrosis is found in 0.8% of breast tumors and in 1% of women who undergo breast reduction surgery.

Yes, it can. Breast fat necrosis is a benign (noncancerous) condition, but the lumps can feel like cancer tumors. A clinical exam and mammogram can differentiate between cancerous and noncancerous tumors.

Yes, the condition may go away on its own. If it doesn’t, you may need to have it surgically removed. One option for removal is liposuction and another is a lumpectomy.

Yes, it can grow in different parts of the breast. It can also shrink.