Dermatofibrosarcoma Protuberans (DFSP)
Clinical Presentation
Dermatofibrosarcoma protuberans (DFSP) is a rare type of skin cancer that develops in the dermis of the skin. The skin is made up of three layers: the epidermis (top layer), dermis (middle layer), and subcutaneous fat (bottom layer). DFSP grows slowly and rarely spreads to other parts of the body. This is called metastasis. Lesions may go unnoticed for months or years. It forms most often on the torso of the body, especially the shoulders and chest. The torso (also called the trunk) is the area of the body between the neck and groin that does not include the arms or legs. DFSP can also form on the limbs (arms and legs) as well as the head and neck.
Lesions usually begin as painless, rough patches of skin that are flat and may be red, purple, or flesh-colored. Over time, the tumor grows and pushes into the epidermis, the top layer of skin. This causes the formation of firm lumps of tissue or protuberances called nodules that may be painful and bleed. Skin injuries, such as burns, tattoos, or scars, may increase the risk of developing DFSP. One type of DFSP is called fibrosarcomatous transformation of dermatofibrosarcoma protuberans (FS-DFSP). It is an aggressive form that often comes back and spreads to other parts of the body.
Preliminary Workup
If you have a skin lesion that may be cancerous, your doctor will ask about your past medical history and perform a physical exam. It is important to share information about your family history. This can help your doctor determine if there could be a genetic cause for your condition. During the physical exam, your doctor will perform a complete skin exam. This involves visually inspecting the skin for moles, birthmarks, scars, and other spots that may be signs of skin cancer.
Your doctor may order an MRI (magnetic resonance imaging) scan with contrast before performing a biopsy to help plan your treatment. This type of scan uses magnets and radiowaves to determine the size and depth of the tumor. Contrast is a liquid dye that is injected to make it easier to see certain tissues. Biopsies on lesions suspected to be skin cancer involve removing a sample of tissue from the lesion that will be sent for testing. The types of biopsies recommended for DFSP are punch, incisional, and core needle biopsies. Punch biopsies remove tissue with a short cylinder similar to an apple core. Incisional biopsies remove part of the tumor with a scalpel or surgical knife. Core needle biopsies remove tissue with a large, hollow needle. To accurately diagnose DFSP and identify FS-DFSP, tissue from the deeper subcutaneous skin layer is necessary.
Tissue samples from the biopsy are sent to the laboratory for special tests. These will help your doctor diagnose the type of skin cancer you have. A pathologist is a physician trained to examine cells and tissues to identify diseases. They often use special stains or chemicals that make it easier to see parts of cells or tissues under a light microscope. Hematoxylin and eosin (H&E) staining and immunostaining are the most common stains used to diagnose DFSP. H&E stains make the nucleus of the cell appear purple and the rest of the cell pink. Immunostaining uses antibodies that attach to proteins on the surface of cells.
Diagnosis
The diagnosis of DFSP and FS-DFSP is based on the tumor's appearance and location, as well as the biopsy results. This type of tumor is frequently misdiagnosed due to inadequate tissue samples. Another biopsy may be necessary if your doctor suspects DFSP. Most tumors can be diagnosed with H&E staining. Sometimes, it may be difficult to distinguish DFSP from a benign or non-cancerous skin lesion called dermatofibroma. In these cases, immunostaining may help diagnose the condition.
Additional Workup
Dermatofibrosarcoma protuberans is a rare cancer. Many doctors are not experts in diagnosing and treating it. Your doctor may refer you to a center that has experts with experience treating DFSP and FS-DFSP. This is especially important if you have a large tumor. It is also important if recurrence or spread to other areas of the body is suspected. Treatment decisions in these cases can be complex. Also, some types of treatment, like clinical trials, are only available at certain treatment centers or hospitals.
Treatment
The initial treatment for DFSP is surgery. The goal of surgery is to remove all or as much of the tumor as possible to prevent it from returning. Mohs micrographic surgery and other forms of peripheral and deep en face margin assessment (PDEMA) are recommended to treat DFSP. Another type of surgery called wide local excision (WLE) is not recommended. This is because it has high rates of recurrence. Mohs micrographic surgery is the most common form of PDEMA used to treat skin cancer. The surgeon removes the tumor along with a small amount of healthy-looking tissue. They use a microscope to examine the tissue edges or margins for cancer cells. If cancer cells are present, the surgeon removes more tissue. This process is repeated until the margins are clear meaning that there are no cancer cells seen.
DFSP cancers may grow deep into the lower layers of the skin making it difficult to remove the entire tumor. Your doctor may recommend a second treatment after surgery. This can help kill any remaining cancer cells. Radiation and chemotherapy are two options available. Radiation treatments can prevent the tumor from returning. However, they carry long-term risks, like developing a different cancer. Imatinib is a chemotherapy medicine. It can treat DFSP when surgery cannot, or if DFSP recurs or spreads.
References
1. American Academy of Dermatology Association. Skin cancer types: dermatofibrosarcoma protuberans overview. https://www.aad.org/public/diseases/skin-cancer/types/common/dfsp
2. Brooks J, Ramsey ML. Dermatofibrosarcoma protuberans. In: StatPearls [Internet]. StatPearls Publishing; 2019.
3. Reid AT, Berger A., & Johnson-Jahangir H. Dermatofibrosarcoma protuberans with fibrosarcomatous transformation: a tale of unbridled expansion. JAAD Case Rep. 2020; 6(10):1006-1008. doi: 10.1016/j.jdcr.2020.07.053
© 2025 Dena Aruta. All rights reserved.
