Question: What is (are) Dermatofibrosarcoma protuberans ?
Answer: Dermatofibrosarcoma protuberans is an uncommon cancer in which tumors arise in the deeper layers of skin. The tumor usually starts as a small, firm patch of skin; it may be purplish, reddish, or flesh-colored. It is commonly found on the torso, usually in the shoulder and chest area. The tumor typically grows slowly but has a tendency to recur after being removed. It rarely spreads to other parts of the body. The cause of DFSP is unknown, but injury to the affected skin may be a predisposing factor. Treatment usually involves surgically removing the tumor. If the tumor is unable to be removed completely, additional therapy may be needed. Regular follow-up is important to monitor for recurrence.
Source: GARD

Question: What causes Dermatofibrosarcoma protuberans ?
Answer: What causes Dermatofibrosarcoma protuberans? The cause of DFSP is unknown but an injury to the affected skin may be a predisposing factor. Trauma at the affected site has been reported in approximately 10-20% of patients. Recent advances have shown that in approximately 90% of cases, dermatofibrosarcoma protuberans is associated with a rearrangement (translocation) of genetic material between chromosomes 17 and 22 which results in the fusion of two genes. The fused gene produces a protein which some believe may stimulate cells to multiply, leading to the tumor formation seen in dermatofibrosarcoma protuberans. This type of gene change is generally found only in tumor cells and is not inherited.
Source: GARD