Intraductal papillary mucinous neoplasm: Mucin-producing cystic tumor arising from main &/or branch pancreatic ducts with low malignant potential

Previously called: Intraductal papillary mucinous tumor, duct ectatic mucinous cystadenoma, mucinous hypersecretory neoplasm, mucin-producing tumor

Cystic neoplasm of pancreas arising from mucin-producing epithelium of main pancreatic duct (MPD) &/or side branch pancreatic ducts (SBD) with variable malignant potential

US: Not modality of choice: Difficult to evaluate entire pancreas due to bowel gas and limited characterization

MPD type: Dilated MPD > 5 mm, may contain low-level internal echoes (mucin vs. mural nodule); without obstructive mass

SBD type: Multicystic, grape-like cluster of anechoic or hypoechoic masses; may see communication with dilated pancreatic duct

Mixed type: Findings of both types

Typically in head/uncinate

May be multiple (21-40%); entire pancreas in up to 20%

Endoscopic US (EUS): Provides best morphologic evaluation and opportunity for cyst aspiration &/or biopsy

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  Higher spatial resolution than transabdominal US; can depict internal septations, mural nodules, wall thickening

CT or MR: Important in identifying features associated with increased risk of malignancy

MRCP: Best noninvasive imaging modality for identification of ductal communication

Follow-up surveillance imaging with CEMR/MRCP

Pancreatic pseudocyst

Chronic pancreatitis

Mucinous cystic pancreatic neoplasm

Pancreatic serous cystadenoma

Pancreatic ductal adenocarcinoma

Main duct type: Precursor to invasive ductal carcinoma

Branch duct type: Generally benign, low malignancy risk

Mean at diagnosis: 68 years; range: 60-80 years; M > F

Nausea/vomiting, abdominal pain, weight loss, anorexia

MPD type may result in pancreatitis

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  From obstruction secondary to excess mucin production

Tanaka criteria (update to Sendai classification): Classifies intraductal papillary mucinous neoplasm as high risk, worrisome, or low risk based on imaging features in order to guide treatment decisions

If high-risk stigmata present based on Tanaka criteria → surgical resection

If worrisome features present → EUS for biopsy/aspiration

If no worrisome features present → follow-up interval determined by cyst size

Look for communication between cystic lesion and pancreatic duct, which may be dilated