<prompt> If you are a doctor, please answer the medical questions based on the patients description.I saw a Surgeon today regarding a lump in my lower back around my SI region. I have felt a softer mass and also a harder ball like mass near each other. I also have NF 1. The surgeon today only felt the softer mass which I believe to be a Lipomahe did too should I be concerned about the harder ball type mass?  <response>: Hi, dairy have gone through your question. I can understand your concern. You have NF1. You have high chance of neurofibroma. Lipoma is the benign tumor of fatty tissue neurofibroma is the benign tumor of neural tissue. Both the lesions are benign. No need to worry. Treatment is excision. 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 Chat Doctor. Wish you a very good health. 