An Overview of Breast Fat Necrosis

Breast fat necrosis (tissue death or damage) is a benign condition that can cause noncancerous lumps that feel like breast cancer and look like tumors on a mammogram. It accounts for 2.75% of all breast lesions. These lumps can occur in anyone, but they're more common in assigned females at or around the age of menopause.

Breast fat necrosis can occur due to injury, after breast reduction surgery or cancer treatment, or due to blood thinner therapy. People with large breasts or those diagnosed with obesity also may experience it; a higher risk of cancer is linked to obesity in some people, even though the necrosis itself doesn't cause breast cancer.

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

Symptoms of Fat Necrosis in Breasts

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:

• Lumps that are often periareolar (around the areola, which is outside the nipple) and superficial (felt just under the skin)
• Bruising or tenderness
• Skin tethering or dimpling
• Nipple retraction

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.

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% to 25% of people.

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 may 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—but fat necrosis may depend on radiation exposure level.

Breast Surgery

Any type of breast surgery can damage the fatty tissue, including:

• Biopsies (used to remove tissue samples for lab tests)
• Reconstruction
• Reduction
• Fat transfer (lipomodeling, which is moving fat from another part of the body and injecting 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. Fat necrosis also is a concern with fat grafting during reconstruction since it can be difficult to differentiate fat necrosis from a breast cancer recurrence.

Other Causes

Rarely, breast fat necrosis may be due to another health condition, including:

• Polyarteritis nodosa (a serious inflammation of blood vessels)
• Weber-Christian disease (a spectrum of skin disorders that may affect the breast)
• Granulomatous angiopanniculitis (a type of panniculitis that causes inflammation)
  

Diagnosis

Fat necrosis can be difficult to diagnose because it often looks and feels like many other types of breast lumps during a clinical breast exam.

A mammogram, ultrasound, or magnetic resonance imaging (MRI) may identify a mass that looks like a malignant breast tumor: dense, with an irregular shape, a spiky border, and a collection of microcalcifications (tiny calcium deposits). An 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. 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.

A study of breast fat necrosis after cancer treatment found that 60% of cases will resolve by themselves without the need for a procedure. However, large masses may be surgically removed if causing pain or discomfort. 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.

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 diagnose this condition and guide treatment.

Most cases of breast fat necrosis can be resolved with at-home remedies, like warm compresses, massage, and over-the-counter pain relief. Rarely, surgery may be used to remove a large lump.

Fat necrosis can be a challenge for healthcare providers. That said, through a combination of imaging studies and a biopsy, a diagnosis is possible. Talk to your healthcare provider to be sure the changes you're experiencing are remnants of past damage to your breast tissue and nothing more.