I am only a layman - my best guesses are that your previous lesion - unknown type - has not recurred. But there is a new lesion that is not a tumor but a cyst (which is good since it cannot be cancer). Not sure the size give the info - the subependymal cyst when I looked it up appears to be more common in infants or can be caused by infections?
Let us know what your doctor says. Best of luck!
huh? what kind of tumor did you have?