Dermatofibrosarcoma protuberans: (DFSP) A type of skin tumor that begins as a hard nodule and grows slowly. DFSP is usually found in the dermis of the limbs or trunk of the body. (The dermis is the inner layer of the two main layers of tissue that make up the skin.) DFSP can grow and invade surrounding tissues but typically it does not metastasize (spread) to other more distant parts of the body.
The cytogenetic hallmark of DFSP is an extra ring chromosome containing material from chromosomes 17 and 22, or, less frequently, a translocation between chromosomes 17 and 22. These chromosome rearrangements in DFSP fuse the COL1A1 gene on chromosome 17 to the PDGFB gene on chromosome 22. COL1A1 is type 1 alpha-1 chain of collagen while PDGFB is platelet-derived growth factor receptor B. The treatment of choice for DFSB is surgical excision or Mohs surgery.