Dermatofibrosarcoma protuberans (DFSP) was first identified as a distinct medical condition in 1924 by a German dermatologist, Hoffmann, who described it as a unique type of skin tumor. At that time, it was initially referred to as a progressive and recurring dermatofibroma.
The understanding of DFSP evolved over the years, and it was later classified as a form of soft tissue sarcoma, distinct from other benign fibrous growths. Advances in pathology, genetic analysis, and imaging techniques have since contributed to a more precise diagnosis and treatment approach for this rare cancer.
Dermatofibrosarcoma protuberans (DFSP) is a rare type of soft tissue sarcoma that forms just beneath the skin. This cancer typically arises in the dermis (middle layer of the skin) and can extend into underlying fat, muscle, and fascia (the connective tissue supporting muscles, organs, and blood vessels). Over time, it may invade deeper tissues if left untreated.
DFSP is most commonly found on the torso—encompassing the chest, abdomen, pelvis, and back—but can also appear on the arms, legs, head, or neck. While it accounts for less than 1% of all soft tissue sarcomas diagnosed annually in the U.S., it most frequently affects individuals in their 30s, 40s, and 50s. Although DFSP grows slowly and has a tendency to recur after treatment, it rarely metastasizes (spreads).
According to statistics from sarcoma.uk.org, an average of 147 cases of dermatofibrosarcoma protuberans (DFSP) are diagnosed annually in England. DFSP accounts for 3.73% of all soft tissue sarcomas and approximately 0.05% of all cancers. While DFSP can occur at any age, the median age at diagnosis is 44 years. Slightly more women than men receive a DFSP diagnosis.
Symptoms and Development
DFSP often begins as a firm area under the skin, with overlying skin discoloration ranging from grayish to red-brown. As it progresses, the tumor may form multiple pimple-like nodules that appear red-brown or violet. Tumors can grow steadily, reaching sizes of up to 5 centimeters. In some cases, they may cause painful open wounds.
Subtypes of DFSP
DFSP is categorized into several types:
- Conventional DFSP: The most common type, with a low likelihood of spreading unless recurrent.
- Fibrosarcomatous DFSP (FS-DFSP): Features aggressive behavior, higher recurrence, and increased spread risk.
- Giant Cell Fibroblastoma: Primarily affects children and teens, with larger cell structures.
- Myxoid DFSP: Contains myxoid stroma, a distinct type of tissue.
- Pigmented DFSP (Bednar Tumor): Features dark cells and is more common in the Black population.
Causes and Risk Factors
Dermatofibrosarcoma protuberans (DFSP) develops due to a genetic translocation involving chromosomes 17 and 22. This specific mutation leads to the fusion of two genes, COL1A1 and PDGFB, which promotes abnormal cell growth and the development of DFSP tumors. Unlike some cancers that are passed down through families, this genetic alteration occurs spontaneously and is not inherited.
Although the precise triggers for this mutation remain unclear, researchers have identified potential risk factors that may increase the likelihood of developing DFSP. One area of ongoing study focuses on prior skin injuries, such as scars from surgeries, burns, or trauma. In some cases, DFSP has also been observed to arise in areas of skin with tattoos or chronic inflammation.
While these connections suggest that environmental or physical factors may play a role in tumor formation, the evidence remains inconclusive. Researchers continue to investigate how external influences, combined with genetic predisposition, may contribute to the development of DFSP. Understanding these causes and risk factors is essential for improving prevention and early detection strategies for this rare cancer.
Diagnosis and Staging
Doctors start the diagnosis with a physical examination and biopsy, analyzing a small tumor sample for cellular and genetic characteristics. They may also perform imaging studies, such as MRIs, to determine the tumor’s size and depth.
Treatment Options
Treatment primarily involves surgical removal of the tumor. There are two surgical approaches:
- Mohs Surgery: Removes cancer must be layer by layer, ensuring all cancerous tissue is excised.
- Wide Excision: Removes the tumor in one piece along with a margin of healthy tissue to minimize recurrence risk.
When surgery cannot remove the tumor or it recurs, doctors use targeted therapies like imatinib to inhibit cancer growth. They may also recommend radiation therapy if surgery does not achieve clear margins.
Radiation therapy uses high-energy beams, such as X-rays or protons, to destroy cancer cells. Targeted therapy focuses on attacking specific chemicals within cancer cells. By blocking these chemicals, targeted drugs like imatinib (Gleevec) can kill cancer cells, particularly in cases where dermatofibrosarcoma protuberans produces excess proteins. This treatment option may be recommended if cancer recurs after surgery. Additionally, clinical trials exploring new treatments might be available. Speak with your provider to determine if you qualify for participation in a clinical trial.
Long-Term Management
Regular follow-up appointments are essential to monitor for recurrence. These may include physical exams, imaging, and discussions about any new symptoms. A multidisciplinary team provides comprehensive care, guiding patients from diagnosis through long-term management.
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Here is a page that provides an overview of sarcoma and its most common subtypes.
Resources: PennMedicine
