I asked on one of my dog groups and got this reply:
"My dog nearly died of pancreatitis which stabilised and became diabetes. She
stabilised fairly quickly and apart from cataracts which set in very quickly,
she is quite chipper.
This dog sounds to be suffering from an added complication, although what
it is I have no idea. I imagine the vet may be thinking a growth on the pancreas. I hope things improve when they stabilise the diabetes."
Sorry if its not much help, but if there are any other replies I will post them.