Can pancreatitis turn into cancer. can one be mistaken for the other by an oncologist?

Yes but rare: Chronic pancreatitis is a long-term inflammation of the pancreas. This condition is linked with an increased risk of pancreatic cancer (especially in smokers), but most people with pancreatitis never develop pancreatic cancer. The two can be hard to tell apart and usually require a biopsy to prove the nature of the process.

No: by definition pancreatitis is inflammation caused by many factors such as stones and meds such as steroids causing vascular changes in brances from spenic artery feeding the pancreas. Ca of pancreas begins 15 years or more before clinical disease and develops in mucosal lining of duct that slowly transforms probably viral in etiology.