This skin cancer tends to grow slowly so it often goes unnoticed for months or even years. Dermatofibrosarcoma protuberans (DFSP) can form anywhere on the skin but they are most likely on the trunk (chest, back, belly, shoulder, buttocks), arms or legs.  Few DFSP form above the neck but it is possible to find them on the scalp or inside the mouth.  DFSP is more common in younger people, usually between the ages of 20 and 50.

When DFSP first appears on the skin, the following may be noticed:

• A slow-growing, painless, pimple-like growth that may be hard. It may look harmless and look similar to a common innocent skin growth called a dermatofibrosarcoma.

• A non-tender reddish brown or pink, raised, rough patch of skin. This may resemble a scar.

• As DFSP grows, it expands the middle layer of skin and pushes on the top layer of skin. This may result in a hard or rubbery lump known as a protuberan. As the lump grows, it stretches the skin and may become tender, crack and bleed or feel fixed or cemented in the skin. Over time, more lumps can appear and once this happens, the DFSP tends to grow quickly. In adults, the protuberans range in color from reddish-brown to purple. In young patients, they tend to be blue or red.

When a woman is pregnant, DFSP tends to grow more quickly.

Scientists do not yet know what causes DFSP. In treating patients with DFSP, dermatologists have learned that this cancer sometimes begins on skin that was badly injured. The injured skin may have a scar from a burn or surgery. Sometimes, DFSP forms where a person received a vaccination or many radiation treatments.  More research is needed to know whether a skin injury truly plays a role in causing DFSP.

People of all ages and races get DFSP. Most people are diagnosed between the ages of 20 and 50. Although unusual, children can get DFSP or a child is born with it. In newborns, this skin cancer resembles a birthmark.

In looking at US cancer records, dermatologists found that between 1973 and 2002, blacks were slightly more likely than whites to get DFSP. Among whites, those living in Hawaii had the highest incidence.  Cases of DFSP are increasing, especially in whites.

Diagnosis begins with an exam. Your dermatologist will closely examine your skin looking for suspicious spots. When one is identified, a biopsy will be performed. The only way to diagnose DFSP is with a skin biopsy. Your dermatologist can perform this procedure during an office visit.

A skin biopsy should not cause anxiety. To perform a skin biopsy, your dermatologist will numb the suspected growth then remove part or all of it with a scalpel, punch or razor blade. Your dermatologist will send this to a laboratory to be looked at under a microscope. The findings will be communicated in a biopsy report.

Once the diagnosis has been made, you will need a thorough physical exam. You may also need additional tests that will provide information necessary to create a treatment plan for DFSP.  Your dermatologist may create the treatment plan but often doctors from other specialties including surgical oncology (cancer specialist) and plastic surgery may be involved.  Most treatment plans include surgery to remove the cancer.  Because DFSP can grow deep, additional treatments may be necessary.

Surgical treatment options are:

• Excision:  This surgery involves numbing the area to be treated and cutting out any remaining tumor along with some surrounding tissue that may look healthy. This helps catch cancer that may not be visible to the naked eye.  Like the skin biopsy, this removed skin is examined under a microscope to ensure that the entire tumor has been removed.
• Mohs micrographic surgery: Named for the doctor who developed this surgery, Mohs (pronounced moes) is a surgery performed by a specialist to remove certain skin cancers. This surgery gives a high cure rate and limits the amount of normal skin that has to be removed around the cancer.  Your dermatologist will tell you if Mohs is right for you.  With Mohs surgery, the surgeon will cut out the tumor plus a small amount of normal-looking skin surrounding the tumor. While you wait, the Mohs surgeon uses a microscope to determine if there are left over cancer cells. If cancer cells remain, the surgeon will continue to remove small amounts of skin and look at them under the microscope. This continues until the surgeon no longer sees cancer cells.
• Reconstructive surgery: Since DFSP grow deep, the resulting wound from surgery can be large. Some patients will need reconstructive surgery to repair this wound. When DFSP grows into the lower layer of skin, it often spreads out like roots of a plant. This root-like growth can make it difficult to remove all of the cancer.  To reduce the risk of DFSP returning after surgery, a second treatment may be needed.
• Radiation treatments: After surgery, some patients receive radiation. These treatments can destroy cancer cells. Because of the long-term risks of radiation, doctors must carefully consider both benefits and risks of this treatment.  In a small study, researchers followed 14 patients who received radiation after surgery. Most patients, 86%, remained cancer-free for over 10 years.
• Combination treatment with excision and Mohs surgery: In a small study, the cancer did not return when patients received both surgical treatments.
• Imatinib mesylate: The US Food and Drug Administration (FDA) has approved this medicine to treat DFSP in adults when the cancer cannot be treated with surgery, returns after treatment or has spread to other parts of the body. Imatinib is designed to target specific cancer-causing molecules. This gives it the power to kill cancer cells while preventing serious damage to non-cancerous cells.  This medicine is not right for every patient who has DFSP. For this medicine to work patients must have certain DNA and testing is required to find out whether a patient has that DNA. If your doctor prescribes imatinib, you will need to be carefully supervised.  After taking imatinib, some patients are able to have surgery because the drug shrinks the DFSP enough so the cancer can be surgically removed.

Images used with permission of Journal of the American Academy of Dermatology:

• Bichakjian CK, Alam M, Andersen J et al. “Dermatofibrosarcoma protuberans: Clinical practice guidelines in oncology.” National Comprehensive Cancer Network. Version 2.2013.
• Buck DW, Kim JY, Alam M, “Multidisciplinary approach to the management of dermatofibrosarcoma protuberans. J Am Acad Dermatol. 2012;67(5):861-6.
• Criscione VD, Weinstock MA. “Descriptive epidemiology of dermatofibrosarcoma protuberans in the United States, 1973 to 2002.” J Am Acad Dermatol. 2007;56(6):968-73.
• Gloster HM. “Dermatofibrosarcoma protuberans.” J Am Acad Dermatol. 1996;35(3 Pt 1):355-74
• Halpern M, Chen E, Ratner D. “Sarcomas.” In Nouri K. [editor]. Skin Cancer. United States. McGraw Hill Medical; 2008. p. 217-18.
• Irarrazaval I, Redondo P. “Three-dimensional histology for dermatofibrosarcoma protuberans: case series and surgical technique.” J Am Acad Dermatol. 2012 Nov;67(5):991-6.
• Kurlander DE, Martires KJ, Chen Y et al. “Risk of subsequent primary malignancies after dermatofibrosarcoma protuberans diagnosis: a national study.” J Am Acad Dermatol 2013;68(5):790-6.
• Thornton SL, Reid J, Papay FA, et al. “Childhood dermatofibrosarcoma protuberans: Role of preoperative imaging.” J Am Acad Dermatol 2005;53:76-83.