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Intraductal Papillary Mucinous Neoplasms (IPMNs) are mucin-producing epithelial neoplasms arising from the pancreatic ducts characterized by papillary proliferation of ductal epithelium, mucin secretion, and variable degrees of dysplasia.

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• Considered precursor lesions to pancreatic adenocarcinoma.

Etiopathology

Pathogenesis:

• Arises from pancreatic ductal epithelium → papillary growth with mucin production → ductal dilatation.
• Progression pathway: IPMN (adenoma → borderline → carcinoma in situ) → invasive carcinoma.

![Revised Progression Model of Intraductal Papillary Mucinous Neoplasm.

Hu Y, Jones D, Esnakula AK, Krishna SG, Chen W. Molecular Pathology of Pancreatic Cystic Lesions with a Focus on Malignant Progression. Cancers. 2024; 16(6):1183. https://doi.org/10.3390/cancers16061183](attachment:aa076a1d-fc31-4b87-8863-64c3b1fd67eb:cancers-16-01183-g001.png)

Revised Progression Model of Intraductal Papillary Mucinous Neoplasm.

Hu Y, Jones D, Esnakula AK, Krishna SG, Chen W. Molecular Pathology of Pancreatic Cystic Lesions with a Focus on Malignant Progression. Cancers. 2024; 16(6):1183. https://doi.org/10.3390/cancers16061183

Risk factors:

• Advanced age (60–70 years).
• Male predominance (esp. main-duct type).
• Smoking, chronic pancreatitis, family history of pancreatic cancer.

Histology (subtypes based on epithelial differentiation):

1. Gastric type – often branch-duct IPMN, low malignant potential.
2. Intestinal type – often main-duct, risk of invasive colloid carcinoma.
3. Pancreatobiliary type – higher grade, risk of tubular adenocarcinoma.
4. Oncocytic type – rare, aggressive.

Immunohistochemistry:

• MUC1, MUC2, MUC5AC patterns help subtype classification.

Clinical Features