<s>[INST] I have a large lump on my head I think it s been there for years. I ve had a ct scan and even though the doctor isn t sure if it s a lesion on part of my scull wants to do an operation on it to see what it is. I m not sure although I ve just had a pre op. I ve only just received my results today. The doctor also said nothing had gone into my brain and he said he wasn t happy with the ct results ie he would of liked to see more. So why would he do this procedure instead of another ct scan??? Thanks Sam [/INST] Welcome to Chat Doctor. 1. The history and the symptoms suggest there is lump on the head which is unsatisfactory on CT scan.2. This suggests possibility of the bone involvement - bony lump with intracranial involvement. 3. This is only possibility - as you have to mention the findings in the CT scan. 4. In this case I would recommend the next step will be FNAC / BIOPSY - fine needle aspiration cytology or biopsy.5. That will help to identify the nature of the cells involved. And treatment will be accordingly. Good luck. Hope I have answered your query,anything to ask ? Do not hesitate to ask.http://doctor.ChatDoctor .com/doctors/ Chat Doctor.  </s>