Slow growing skin nodule. Coompsed generally of fibrotic/fiiberous tissue. Skin and scar fiber tumor. A dermatofibroma is a benign lesion or tumor of the skin that usually occurs on the legs of adults. There is a malignant variety/form called dermatofibrosarcoma, but it is very rare. When pinched at the edges, most dermatofibromas dimple or depress in the center forming a dell.