What is the cyst marker profile for an intraductal papillary mucinous neoplasm (IPMN)?

• A. KRAS mutation, low amylase, high CEA
• B. No mutation, high amylase, high CEA
• C. KRAS/GNAS/BRAF mutation, variable amylase, high CEA
• D. CTNNB1 mutation, low amylase, low CEA

Answer: (C)

IPMN cysts are mucinous pancreatic lesions that carry characteristic genetic and fluid markers. In these cysts, KRAS and GNAS mutations are commonly found, with BRAF mutations seen in a subset; this genetic pattern supports a mucinous, duct-related neoplasm. The cyst fluid often has high CEA due to mucin production, while amylase can vary because the cyst may or may not communicate with the pancreatic duct.

So a profile showing KRAS and GNAS mutations, sometimes a BRAF mutation, high CEA, and variable amylase fits IPMN best. The presence of a mucinous marker (high CEA) and duct-related biology (variable amylase) together with these mutations makes this choice the most consistent interpretation. Profiles with no mutations, beta-catenin–driven patterns, or consistently low CEA are less typical for IPMN.