What does it mean when fluid develops around pancreatic tumor?

Inflammation. Pancreatitis is an inflammation of the pancreas. This can occur when the ducts within the pancreas become obstructed. It can also occur if there was a recent pancreatic procedure (like a biopsy). It can also occur after eating too much greasy food or alcohol.
Depends. Fluid after pancreatic surgery can be simply reactive to the surgery. Fluid not related to surgery, can be reactive to malignancy or malignant cells. Generally fluid related to pancreatic cancer is malignant ascites. It makes treatment of pancreatic cancer difficult, and typically makes the treatment palliative.