<s>[INST] From time to time I have a feeling of being off balance with a weird feeling in my head. Had an MRi with contrast and I have found out that I have a tumor at the base of my brain. Was told that I was most likely born with this. I have had several MRI and nothing changes. I do have sinus problems. I am 65 years old. I also have severe night sweats . This is not a feeling of dizziness as I had in the past and had the Epstein Barr procedure done. What could be the cause of this? [/INST] Hi, Thank you for posting your query. Brain tumor could be related to your imbalance. However, it would be immensely useful if you could upload the MRI report, to understand the size and location of the tumor. Vitamin B12 deficiency should also be excluded as a cause of your symptoms. No change in the MRI means that surgery is most likely not needed for the tumor. Best wishes, Dr Sudhir Kumar MD DM (Neurology) Senior Consultant Neurologist Apollo Hospitals, Hyderabad </s>