Hello @qlovej and welcome to the Head and Neck group. Polymorphous adenocarcinoma is a rare situation indeed. It appears to be treatable by anyone familiar with this salivary gland tumor but it may prove difficult to find anyone familiar unless you consult a large clinic or cancer center.
I really can’t give you any more information than what you can find on the internet. I can only find one case with Mayo Connect and that was a couple years back with a person known as @sugardog , which you can search out using the search bar above.
Give this discussion a few days and someone might pop in with something.
Any treatment suggestions yet? Many of us here can help you with surgery and radiation advice.