Dermatofibrosarcoma protuberans (DFSP) is a rare form of skin cancer. While a malignancy, DFSP is generally slow-growing and rarely proves fatal. Its behavior differs from more aggressive cancers, and its life-threatening potential is limited.
Defining Dermatofibrosarcoma Protuberans
Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma that originates in the dermis, the middle layer of the skin. This tumor typically presents as a firm, raised nodule or plaque, often appearing discolored in shades of red-brown, violet, or pink. Over time, these lesions can grow slowly, sometimes forming a larger protuberance on the skin surface.
DFSP can develop anywhere on the body, but is most commonly found on the trunk, including the chest, back, shoulders, abdomen, and buttocks. Other frequent locations include the extremities, head, and neck. It affects approximately 4 out of every 1 million people worldwide each year.
Growth and Spread of DFSP
A defining characteristic of DFSP is its pattern of local invasion. The tumor grows deeply into surrounding tissues, extending microscopic, tentacle-like projections far beyond the visible lesion. These projections can infiltrate fat, muscle, and even bone, making complete surgical removal challenging. This extensive local growth is the primary reason for its relatively high local recurrence rate if not adequately treated.
Despite this aggressive local behavior, DFSP rarely spreads to distant organs or lymph nodes. The risk of distant metastasis is low, occurring in about 1% to 5% of cases. When distant spread does occur, it most commonly involves the lungs.
Outlook and Chances of Recovery
The prognosis for individuals diagnosed with DFSP is favorable, especially with early detection and appropriate treatment. Due to its slow growth and low metastatic potential, DFSP has high survival rates. The overall 10-year survival rate for DFSP is reported to be around 99%.
Several factors can influence the outlook, including the tumor’s size, its specific histological characteristics, and the completeness of its surgical removal. Larger tumors or those with certain aggressive features may be associated with a slightly higher risk of adverse outcomes. While local recurrence is a common concern after initial treatment, these recurrences typically do not impact overall survival if promptly re-treated. In the rare instances where the disease does metastasize, the prognosis becomes significantly poorer, with median survival for metastatic disease reported to be around two years after diagnosis.
Managing DFSP
The primary treatment for DFSP is surgical removal of the tumor. The goal of surgery is to achieve complete excision with clear margins, meaning no cancer cells are left behind at the edges of the removed tissue. This approach is important for minimizing the risk of local recurrence.
Mohs micrographic surgery (MMS) is often the preferred surgical technique for DFSP. This specialized procedure involves removing the tumor layer by layer, with immediate microscopic examination of each layer to ensure all cancer cells are eliminated while preserving as much healthy tissue as possible. Mohs surgery has demonstrated lower local recurrence rates (1% to 4%) compared to traditional wide excision (10% to 50%). For cases where complete surgical removal is not feasible, or if there are positive margins after surgery, radiation therapy may be used as an additional treatment. In the rare event of recurrent, unresectable, or metastatic DFSP, targeted therapies, such as imatinib, can be employed.