Is there signs to know if the mass which grows quickly in the abdomen to the pancreas causes a benign tumor of pancreas or malignant tumor?

Biopsy: Rapid growth of a tumor is worrisome for cancer. Only a biopsy can give definite answer.

Biopsy: There are generally 2 kinds of "lumps" of the pancreas-- solid lumps are tumors, and fluid lumps are cysts. A solid lump that is growing should have a biopsy sample taken to make sure that under the microscope it doesn't look like cancer. A growing cyst can be treated by removing the liquid with a needle. A surgeon or a gastroenterologist are good resources for these situations.