Son had mri results of: irregular t2 and flair hyperintensity along the left aspect of the body of the corpus callosum. what does this mean?

Many things: This could be a million things. If this is the only finding, this may represent "gliosis", which is scarring in the brain. Children can have strokes in utero. His age makes ms unlikely. They may want to follow up on regular basis if there is any concern for a low grade tumor. In the end, his neurologist who will have seen the images, and your son, will be your guide on what this means.