From MedlinePlus GeneticsDermatofibrosarcoma protuberans is a rare type of cancer that causes a tumor in the deep layers of skin. This condition is a type of soft tissue sarcoma, which are cancers that affect skin, fat, muscle, and similar tissues.
In dermatofibrosarcoma protuberans, the tumor most often starts as a small, firm patch of skin, usually 1 to 5 centimeters in diameter, that is usually purplish, reddish, or flesh-colored. The tumor typically grows slowly and can become a raised nodule. Occasionally, the tumor begins as a flat or depressed patch of skin (plaque). Tumors are most commonly found on the torso and can also be found on the arms, legs, head, or neck. Affected individuals usually first show signs of this condition in their thirties, but the age at which a tumor appears varies widely.
In dermatofibrosarcoma protuberans, the tumor has a tendency to return after being removed. However, it does not often spread to other parts of the body (metastasize).
There are several variants of dermatofibrosarcoma protuberans in which different cell types are involved in the tumor. Bednar tumors, often called pigmented dermatofibrosarcoma protuberans, contain dark-colored (pigmented) cells called melanin-containing dendritic cells. Myxoid dermatofibrosarcoma protuberans tumors contain an abnormal type of connective tissue known as myxoid stroma. Giant cell fibroblastoma, which is sometimes referred to as juvenile dermatofibrosarcoma protuberans because it typically affects children and adolescents, is characterized by giant cells in the tumor.
Rarely, the tumors involved in the different types of dermatofibrosarcoma protuberans can have regions that look similar to fibrosarcoma, a more aggressive type of soft tissue sarcoma. In these cases, the condition is called fibrosarcomatous dermatofibrosarcoma protuberans or FS-DFSP. FS-DFSP tumors are more likely to metastasize than tumors in the other types of dermatofibrosarcoma protuberans.
https://medlineplus.gov/genetics/condition/dermatofibrosarcoma-protuberans