I believe this is an MRI report but they are also using your CT in interpreting the issue. I assume you have had both. CT is excellent in viewing bone. MRI is excellent at imaging soft tissue. The brain is soft tissue.

I know close to nothing about the brain . I'm familiar with medical terminology so maybe I can help qualify some of what this is saying in a very basic way. A lesion is a very broad term and means there is damaged tissue. It is not specific to the brain nor does it say what is wrong. A lesion is different than say a solid tumor. In this case, it appears the lesion is not presenting as anything specific so the radiologist qualifies it as non-specific. They don't quite know what it is. Often lesions and tumors will have unique characteristics that are specific to different diseases/conditions, but this lesion does not. They have a clue, based on your CT, that it may be associated with a rare condition called fibrous dysplasia. I found this explanation online: "Fibrous dysplasia is a rare, benign bone disease. It occurs when abnormal fibrous, scar-like tissue replaces healthy bone." Benign means not cancerous. Again I am not a neurologist, but it sounds like this may be more of a space-occupying problem. The fact that it is there (and could press on other brain structure) could be more of the problem than what the lesion actually is. It doesn't appear to be causing any more issues outside of that at this time. The neurosurgeon is needed to decide if/when to remove it. There doesn't appear to be a big rush or emergency. The neurologist may also not know what it really is either until they remove it and have it biopsied. This doesn't seem to call out any type of brain tumor cancer if that is your greatest fear and creating massive anxiety, particularly if associated with an apparent fibrous dysplasia skull problem. Has anyone discussed that diagnosis with you?