Dermatofibrosarcoma protuberans (DFSP) is a rare type of skin cancer. It starts in the connective tissue cells of the middle layer of the skin. This layer of skin is called the dermis.

The cancer might look like a pimple or feel like a firm patch of skin at first. As it grows, lumps of tissue known as protuberans may form near the surface of the skin. DFSP often forms on the arms, legs and trunk.

Dermatofibrosarcoma protuberans grows slowly and rarely spreads beyond the skin and surrounding tissues. It can look like other skin conditions, so a biopsy is usually needed to diagnose the condition.

DFSP treatment is surgery to completely remove the tumor. The main concern with this cancer is that the tumor can come back in the same place even after it appears to be completely removed. Dermatofibrosarcoma protuberans is rarely fatal.

Symptoms of dermatofibrosarcoma protuberans (DFSP) include:

• A lump or lumps on the skin that look like pimples, scars or birthmarks.
• A lump or lumps on the skin that may feel hard to the touch or rubberlike.
• A patch of skin that feels firm to the touch.

The lumps typically appear on the arms, legs or trunk. They rarely form on the head or neck, but these growths have been found on the scalp and inside the mouth.

DFSP can look like other skin conditions. Usually a biopsy is needed to diagnose this type of cancer and guide treatment.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have ongoing symptoms that worry you. If an area of skin changes or becomes raised, have it checked out.

The cause of dermatofibrosarcoma protuberans (DFSP) often isn't known.

This skin cancer happens when cells in the skin develop changes. The changes happen in the cells' chromosomes. Chromosomes are threadlike structures inside cells that contain DNA and proteins. The changes in the chromosomes cause the cells to grow and divide quickly. The cancer cells form a growth that starts underneath the skin and may push up to create a lump over time. Other lumps may appear as well.

DFSP is not considered an inherited cancer. It doesn't seem to be passed down in families.

Risk factors for dermatofibrosarcoma protuberans (DFSP) include:

• Age. This cancer can happen at any age. Some tumors can be present at birth or develop early in childhood. But it happens most often in adults ages 20 to 50.
• Race. This cancer happens more often in Black people than it does in people of other races.
• Prior skin injury. People with skin that has been burned, treated with radiation or scarred from surgery may be more likely to have this cancer.
• History of DFSP. People who have had this cancer are at risk of it coming back in the same area after surgery.

There is no way to prevent dermatofibrosarcoma protuberans.

Tests and procedures used to diagnose dermatofibrosarcoma protuberans (DFSP) include:

• Skin exam. Your healthcare professional may inspect your skin to look for signs of skin cancer.
• Skin biopsy. Your healthcare professional may remove a small amount of tissue for testing. Tests in the lab can show whether cancer cells are present.
• Imaging tests. Sometimes imaging tests, such as an MRI, are needed to see the extent of the cancer and to help with treatment planning.

DFSP is a sarcoma that can look like other types of skin growths. A biopsy is usually needed for an accurate diagnosis.

Dermatofibrosarcoma protuberans (DFSP) treatment typically involves surgery to remove the cancer. Other treatments may be used to kill cancer cells that might remain after surgery.

Treatment options may include:

• Surgery to remove the cancer. Dermatofibrosarcoma protuberans tends to grow in a shape that's not regular. This makes the cancer hard to remove completely. Your healthcare professional may recommend a procedure to remove the cancer and some healthy tissue around it. A clear margin of healthy tissue around the growth makes it more likely all the cancer cells are removed. That lowers the risk of the tumor coming back.
• Mohs surgery. Mohs surgery is a type of surgery that involves cutting away thin layers of cancer-containing skin until only cancer-free tissue is left. After each layer of skin is removed, it's examined for signs of cancer. The process keeps going until there are no signs of cancer. Mohs surgery may be helpful for treating larger cancers or tumors with borders that are not well defined.
• Radiation therapy. Radiation therapy uses powerful energy beams, such as X-rays and protons, to kill cancer cells. Your health professional may recommend radiation therapy if all the cancer couldn't be removed during surgery.
• Targeted therapy. Targeted therapy medicines attack specific chemicals present in cancer cells. By blocking these chemicals, targeted therapy medicines cause cancer cells to die. This may be recommended if surgery is not an option or if the DFSP returns after surgery. Some people with dermatofibrosarcoma protuberans have cancer cells that produce an excess protein. A medicine called imatinib (Gleevec) can target those cells and cause them to die.

Clinical trials to test new treatments may be an option. Ask your health professional whether you're eligible to participate in a clinical trial.

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you. If your health professional believes you may have skin cancer, that person may refer you to a specialist. Often this is a doctor who specializes in treating skin conditions, called a dermatologist.

Appointments can be short, and being prepared can help. Here's some information that may help you get ready.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms, including any that don't seem related to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medications, vitamins or other supplements you take, including the doses.
• Questions to ask your healthcare professional.

Take a family member or friend along, if possible, to help you remember the information you're given.

For dermatofibrosarcoma protuberans, some basic questions to ask your health professional include:

• Do I have cancer?
• If the lump or lumps aren't cancerous, do I still need to have them removed?
• Do I need more tests?
• What are my treatment options?
• What are the potential risks of these treatment options?
• Do any of the treatments cure dermatofibrosarcoma protuberans?
• Can I have a copy of my pathology report?
• How much time can I take to consider my treatment options?
• Are there brochures or other printed material that I can take with me? What websites do you recommend?
• What would happen if I chose not to have treatment?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you several questions, such as:

• When did your symptoms begin?
• Have your symptoms been happening all the time or do they come and go?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?