Maybe nothing. The first story posted said it was melanoma and it still might be the origin.
I had a Sister in Law who had a small mole that turned out to be melanoma removed from her cheek. About fifteen years later it appeared again, but it showed up as a brain tumor.
The Doctor removed it, but there were others that could not be removed. She died within six months.
Melanomas do not turn into gliomas.
Melanomas do not turn into gliomas.
Source? I know quite a bit about brain tumors and I've been following the Kennedy story throughout the day. Your comment is the first and only one that has referenced melanoma. Every other story has described glioma, an aggressive primary cancerous tumor. A primary tumor means that it did not metastasize to the brain from another site. A glioma originates in the brain and grows very quickly.
My father had a melanoma (back when Senator Kennedy’s brother was President). It metastasized into the brain. He was gone within one year.