Metastatic breast cancer (MBC) most commonly spreads from the breast to the lungs, liver, bones, and brain. But did you know MBC can also affect the skin? This is known as cutaneous MBC (“cutaneous” meaning “related to the skin”), and it can cause noticeable lesions or tumors on your skin. While cutaneous MBC can’t be cured, it can be managed with specialized treatments.

In this article, we’ll discuss what cutaneous MBC is, where and why it develops, and how it’s managed. If you notice any changes in your skin while living with MBC, talk to your oncologist (cancer specialist). They can help make a diagnosis and start you on the right treatment plan.

What Is Cutaneous Metastatic Breast Cancer?

Cutaneous MBC occurs when cancer cells from the primary tumor in the breast spread to your skin. The tumor cells break away and spread via the blood or lymph fluid, forming new tumors on your skin or beneath it. The new tumors are known as metastases.

It’s worth noting that cutaneous MBC is not the same as skin cancers like melanoma. Skin samples taken from cutaneous MBC will contain breast cancer cells. On the other hand, skin cancers come from skin cells that have become cancerous.

How Common Is It?

Research shows that cutaneous metastases occur in around 10 percent of cancer cases with solid tumors, such as breast cancer. Cutaneous MBC accounts for just over half of these cases. Overall, studies suggest that around 30 percent of people with breast carcinoma will develop skin metastases.

Specific aspects of a person’s breast cancer influence their likelihood of developing cutaneous MBC. People with human epidermal growth factor receptor 2 (HER2)-positive breast cancer or triple-negative breast cancer (TNBC) tend to develop cutaneous symptoms earlier. On the other hand, skin symptoms tend to develop later in those with hormone receptor (HR)-positive breast cancer.

Symptoms of Cutaneous MBC

Cutaneous MBC tends to develop near the primary tumor. This means the most common sites for cutaneous MBC are the affected breast or chest wall on the affected side. However, metastatic skin lesions can also develop on:

• The unaffected breast
• Surgical scars from a lumpectomy or mastectomy
• The belly, arms, head, neck, or back

If you have cutaneous MBC, you’ll likely notice changes in the color and texture of your skin. Some people develop nodules or papules (firm, painless lumps) underneath their skin. These lumps form because the new skin lesions block off lymph vessels. Your lymphatic system carries fluid with immune cells throughout your body. The size of the nodules can vary — some are barely noticeable, while others can form large tumors.

Other skin changes you may see with cutaneous MBC include:

• Red or violet patches of skin with visible blood vessels or lymphatic vessels
• Firm, rough, or scarred areas of skin that look and feel similar to the texture of an orange peel
• Pink or red lumps with inflammation that look similar to a severe skin infection known as cellulitis
• Inflammation, swelling, or irritation around the areola or nipple

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Radiation therapy (or radiotherapy) can cause temporary skin rashes, swelling, and skin peeling similar to a sunburn. Studies show that cutaneous MBC may also develop around radiation ports or treatment sites. This can make it difficult to tell apart the two conditions.

Be sure to talk to your oncologist if you notice any new skin changes around your breasts or other areas of the skin.

Complications of Cutaneous MBC

In some cases, the skin around a lesion breaks down and forms an open sore or ulcer. Ulcers require treatment to avoid an infection. If an ulcer becomes infected, it may become painful, have a foul odor, or bleed.

If cutaneous MBC blocks flow through lymph vessels, it can lead to lymphedema. This leads to fluid buildup that can cause new swelling near the metastasis in your breast, arm, or hand.

Cutaneous MBC can also spread to the scalp. This can cause scarring that prevents hair growth. As a result, you may experience hair loss.

Diagnosis of Cutaneous MBC

If your oncologist thinks you may have cutaneous metastasis, they’ll order some tests to confirm the diagnosis. One of the most common tests is a skin biopsy. Your doctor will take a skin sample using one of a few techniques. A punch biopsy uses a rounded cutting tool to “punch” out a small core of skin. An excisional biopsy uses a scalpel to cut and remove an entire lump or area of skin.

After they collect the skin sample, your doctor will send it to a lab. A specialist will stain the sample with different dyes to mark any cancer cells. They’ll then look at it under a microscope for any signs of cutaneous MBC.

Treatments for Cutaneous MBC

After you’ve received a cutaneous MBC diagnosis, your oncologist will go over your options. It’s important to stick with your MBC treatment plan. If you’re taking hormone therapy or a targeted therapy for MBC, it may also help treat your skin symptoms. Chemotherapy is another option if your cutaneous lesions stop responding to targeted treatment.

Localized treatments can also help treat cutaneous MBC. Radiation therapy helps shrink large tumors causing ulcers. Electrochemotherapy (ECT) is a newer treatment that uses electrical impulses to deliver low-dose chemotherapy. ECT can help shrink skin metastases and treat pain and bleeding.

Medicated topical creams have also been studied for treating cutaneous MBC. Several case reports have found that topical ointments containing cancer drugs may be effective when used with cryotherapy, which freezes lesions.

You should also make sure to keep any MBC lesions clean and dry to lower your risk of skin infections. For more specific instructions for at-home care, talk to your oncologist.

Prognosis With Cutaneous MBC

Your prognosis (outlook) with cutaneous MBC depends on details about your primary tumor included in your pathology report. Overall, people with advanced-stage breast cancer tend to live less than one year after they’re diagnosed with cutaneous MBC.

It’s important to remember that everyone’s outlook while living with MBC is different. To learn more about your risk factors, talk to your oncologist.

What MyBCTeam Members Say About Cutaneous MBC

MyBCTeam members have shared their experiences with cutaneous MBC. One member asked, “Has anyone had skin metastasis from breast cancer?”

Another member shared, “I had Paget’s, which is where the invasive ductal carcinoma [IDC] in my breast spread through to the skin, affecting the nipple/nipple skin. That was what made me get checked out in the first place — an itchy, flaky, irritated nipple. It wasn’t until they investigated further that they found the IDC.”

In this case, the member noticed the symptoms of cutaneous MBC before receiving their breast cancer diagnosis. However, some people may not develop skin metastases until after their initial diagnosis. This is why it’s important to talk to your oncologist about any new rashes or lesions.

Another member shared, “I spoke with someone who had a rash on her wrist that was misdiagnosed as dermatitis. They realized after treating it as the wrong thing that it was breast cancer mets.”

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 68,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Are you living with cutaneous metastatic breast cancer? What symptoms have you experienced? What treatments have you tried? Share your story in the comments below, or start a conversation by posting on your Activities page.