Hi, dear I have gone through your question. You may jave dermatofibroma protuberance, benign fibrous histiocytoma or malignant fibrous histiocytoma. You should go for biopsy of that lump. It will give you exact diagnosis. Then you should take treatment accordingly. Excision biopsy is the treatment of choice. Consult your doctor and take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health.