Cystic pancreatic neoplasms
- Lesion
Some pancreatic cysts are tumours: serous ones are almost always benign, mucinous ones can turn into cancer.
What it is
Cystic neoplasms are a minority of pancreatic tumours but are found more often now with imaging. The main types differ in lining, fluid, location, age and sex, molecular drivers and malignant risk. Serous cystic neoplasms are almost always benign; mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMNs) are precursors of invasive adenocarcinoma; solid pseudopapillary neoplasms are low-grade malignant tumours of young women.
Step by step
- Imaging finds a cyst; the first question is pseudocyst versus neoplasm.
- Location, connection to the duct, septa and nodules on imaging narrow the type.
- Cyst fluid analysis (mucin, CEA, cytology, KRAS and GNAS) separates mucinous from serous lesions.
- Mucinous lesions are watched or resected depending on high-risk features (main-duct dilation, nodules, symptoms).
- Resected specimens are graded for dysplasia and invasion.
Cystic neoplasms of the pancreas
| Neoplasm | Who and where | Lining and fluid | Molecular | Behaviour |
|---|---|---|---|---|
| Serous cystic neoplasm | Older women; tail | Glycogen-rich cuboidal cells; thin clear fluid | VHL | Almost always benign |
| Mucinous cystic neoplasm | Women; body or tail | Mucinous columnar cells over ovarian-type stroma; thick mucin; no duct connection | KRAS, RNF43; TP53 and SMAD4 when invasive | Precursor; may become carcinoma |
| Intraductal papillary mucinous neoplasm | More men; head | Papillary mucinous epithelium in main or branch ducts; mucin from the papilla | GNAS, KRAS, RNF43 | Precursor; main-duct type at higher risk |
| Solid pseudopapillary neoplasm | Young women; any site | Poorly cohesive cells around vessels, pseudopapillae, hemorrhagic cystic change | CTNNB1 | Low-grade malignant; usually cured by surgery |
Markers
- Estrogen and progesterone receptors, inhibin (ovarian stroma)
- Nuclear β-catenin (solid pseudopapillary)
- Cyst fluid CEA
Test yourself
Think of the answer, then tap the question to see it.
Which pancreatic cystic neoplasm is almost always benign?
Serous cystic neoplasm (serous cystadenoma), lined by glycogen-rich cuboidal cells.
What separates a mucinous cystic neoplasm from an IPMN?
MCN has ovarian-type stroma and does not connect with the duct system; IPMN arises within and communicates with the ducts.
Which gene is mutated in nearly all solid pseudopapillary neoplasms?
CTNNB1, the gene for β-catenin.
Which IPMN carries the higher risk of invasive carcinoma: main-duct or branch-duct?
Main-duct IPMN.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Pancreatic Cancer Treatment (PDQ®) - NCI (National Cancer Institute, 2026).
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Representative model, for educational purposes only.