Dear Andrew,
I am so sorry to hear about your father-in-law. The Dr. Rosato that did my surgery is the chief surgeon of gastro at the University of Penn and is also a teaching professor. He is very well known and is very good at what he does. I highly recommend him. I don't know if he is the same doctor.
Yes it is possible that the tumor is not cancerous, but I am not an expert. Since pancreatic cancer is one of the most deadliest of all cancers...I would not wait!!!
Please keep me up to date...and please tell your wife that her father is in my prayers. What is his name?
Best regards...Russ