Or, there ain't no "benign" or "malignant" when it comes to your brain
The first thing that most patients ask when they find out they have a brain tumor is "is it malignant?" They want to know if we can take it out, sew them up, and send them home in four days with no need for further treatment.
The first thing most patients ask when their MRIs show white matter lesions is "is that benign?" They want to know if the changes in their brains will lead to them sitting in a chair, reminiscing about something that never happened.
I have a philosophy on that whole question of benign or malignant, and it's this: when it comes to what's happening in your brain-box, all bets are off.
F'rinstance, there's only one brain tumor most of us should lose sleep over: glioblastoma multiforme. Unfortunately, it has the dual distinction of being both the most common type of tumor and the most lethal. You don't get better after a glio, and we can't cure it. It's an extremely aggressive type of tumor that grows fast and interleaves normal tissue with tumor tissue, meaning we can't get it all out.
There are other types of "malignant" brain tumors (meaning they're likely to come back): astrocytomas, metastatic tumors, low-grade gliomas.
There are also plenty of "benign" tumors out there, the most common being the meningioma, which grows on the coverings of the brain rather than in the brain itself.
The problem is this: there is limited space in your skull. Generally speaking, there is only room in there for your brain. If you have a small, easily resectable glioma in a place that's not too valuable, you're likely to live longer and better than somebody with a large meningioma that's compressed tissue in a sensitive spot and done its damage.
It's the same with the various brain lesions that show up on scans.
Most of us, unless we've lived a life free of alcohol, fat, tobacco, caffeine, hypertension, stress, depression, exultation, sadness, and thought, will have white matter lesions in our brains by the time we're 30. Mostly they're not a problem. The only time they start to cause trouble is when they're widespread (like in Alzheimer's) or if they're in sensitive spots. Sometimes they can be a symptom of other things, like hydrocephalus in older folks, which can be more-or-less easily fixed.
Point being, your brain is much like your skin: it shows changes as you get older, but those changes don't generally affect its ability to do its job.
My advice, then, is this: if you're diganosed with tissue changes or a tumor, don't think in terms of benign or malignant. Get a name for the tumor or the changes first, then find out where it is.
If cutting it out will lead to the loss of something that's valuable to you, like your balance or your sense of humor, then it's a bad tumor, no matter what type it is. If cutting it out will allow you to have a good quality of life with minor or no loss of those things that are important to you, then it's a good tumor, no matter what type it is.
If your scan shows changes that are a surprise to you, don't lose sleep over them. If something in your life changed that prompted you to submit to an MRI, then find out if that something could be related to those changes. If it is, find out what the treatments are, and go from there.
"Benign" and "malignant", when it comes to the brain, have more to do with where something is and how it will affect you than *what* it is.