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

Dermatofibrosarcoma protuberans might look like a pimple or feel like a rough patch of skin at first. As it grows, lumps of tissue (protuberans) may form near the surface of the skin. This skin cancer often forms on the arms, legs and trunk.

Dermatofibrosarcoma protuberans grows slowly and rarely spreads beyond the skin.

Diagnosis

Tests and procedures used to diagnose dermatofibrosarcoma protuberans include:

• Skin exam. Your health care provider will inspect your skin to look for signs of skin cancer.
• Skin biopsy. Your provider may remove a small amount of tissue for testing. Tests in the lab can see if 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.

Treatment

Dermatofibrosarcoma protuberans 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. Your health care provider may recommend a procedure to remove the cancer and some of the healthy tissue around it. This makes it more likely that all the cancer cells are removed.

• 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. Dermatofibrosarcoma protuberans tends to grow in an irregular shape that makes it hard to remove completely.

• Radiation therapy. Radiation therapy uses powerful energy beams, such as X-rays and protons, to kill cancer cells. Your provider may recommend radiation therapy if all the cancer couldn't be removed during surgery.
• Targeted therapy. Targeted therapy drugs attack specific chemicals present in cancer cells. By blocking these chemicals, targeted drug treatments cause cancer cells to die. Some people with dermatofibrosarcoma protuberans have cancer cells that produce an excess protein. A drug called imatinib (Gleevec) can target those cells and cause them to die. Your provider may recommend this treatment if your cancer returns after surgery.
• Clinical trials. Clinical trials to test new treatments may be an option. Ask your provider whether you're eligible to participate in a clinical trial.