While I cannot answer the question you've asked, I wanted to thank you for posting it. My mother was diagnosed with Glioblastoma Multiforme with Oligodendroglioma this past January. All of her doctors (and she has dozens) have all stated that this type of cancer wouldn't metastasize! Your entry is the first I've heard that it could. I now have an entirely new topic for my "Things To Research" list!