Updated project metadata. Intraductal papillary mucinous neoplasm (IPMN) is a duct-dilating precancerous lesion that grows in pancreatic ducts and is accompanied by the production of mucinous fluid. In recent years, its cystic fluid has been used molecularly for the differential diagnosis of other cystic tumors and malignancies. Thus, proteomic research of IPMN cyst fluid must be performed to identify an effective diagnostic biomarker. We examined the IPMN cyst fluid proteome using a novel proteomic strategy, combined with high-resolution LC-MS/MS. Although we did not deplete any high-abundance proteins, our dataset consistently detected thousands of proteins including pancreatic tumor markers, such as mucin family members, S100 proteins, and CEA-related proteins. In addition, we found 590 protein mutations through a variant sequence database search. Bioinformatics analyses were performed to determine biological functions and clinical meanings of canonical IPMN proteins and mutated proteins. Our proteomic platform and in-depth proteome dataset are valuable references that can be used in future studies.