Intraductal papillary mucinous neoplasm
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At the time the article was created Frank Gaillard had no recorded disclosures.View Frank Gaillard's current disclosures
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Intraductal papillary mucinous neoplasms or tumors (IPMNs or IMPTs) are epithelial pancreatic cystic tumors of mucin-producing cells that arise from the pancreatic ducts. They are most commonly seen in elderly patients.
On imaging, particularly MRCP, they are characterized by single or multiple unilocular or septated pancreatic cystic lesions communicating with the pancreatic ducts.
These tumors are most frequently identified in older patients, 50-60 years of age 6, and thus are sometimes colloquially referred to as the "grandfather lesion". Main duct type (see below) appears to present a decade or so earlier on average than branch duct type 5. The sex distribution is roughly balanced with a possible slight male predominance 15.
Clinical presentation can be difficult to distinguish from chronic pancreatitis with repeated acute exacerbations. Patients can present with abdominal pain, weight loss, obstructive jaundice, pancreatitis and new-onset diabetes mellitus 5,9.
Intraductal papillary mucinous neoplasms are one of a number of mucinous tumors of the pancreas and can be further divided both histologically and with respect to their macroscopic appearance 5. They are uncommon ductal epithelial tumors comprising 10-15% of cystic pancreatic neoplasms.
Reported locations of IPMN include 15:
uncinate process ~4%
elsewhere throughout the pancreas ~40%
reminiscent of chronic pancreatitis
segmental or diffuse distribution
highest malignant potential 6
~60% are malignant 10
branch duct type
mostly seen in the head and uncinate process
more localized and mass-like
may be multifocal 13
may be macro- or microcystic in appearance 5
typically indolent behavior 6
~5% (range 2-10%) are malignant 11,12
similar to the main duct type in terms of prognosis and overall survival
Solid components, as well as bile duct dilatation 14, are suspicious of malignant transformation.
They are histologically divided into:
intraductal papillary mucinous adenocarcinoma
In patients without pancreatitis, abnormal (either elevated or depressed) pancreatic enzyme markers (amylase/lipase) are associated with malignant IPMN, with the elevation of these a marker of invasiveness 8.
The characteristic feature is that these tumors communicate with the main pancreatic duct or its branches, which helps to distinguish these tumors from mucinous cystadenoma/cystadenocarcinoma, which do not.
Calcifications have been reported in retrospective imaging analyzes of resected IPMN at an incidence of ~12.5% (range 5-20%) 17-21, however, the overall incidence of calcifications in all IPMNs (i.e. resected and unresected) is not known (c.2023) and, interestingly, calcifications are not a criterion in the Fukuoka consensus guidelines to help guide whether surgical treatment is appropriate and are much more common in other pancreatic cystic lesions (e.g. serous cystadenomas).
Direct imaging of the pancreatic duct demonstrates variable dilatation (segmental or diffuse or branch) depending on the type. Polypoid mural tumor or amorphous mucinous luminal filling defects may be identified 5.
Mucinous material may be seen protruding from the ampulla of Vater 6.
Ultrasound may demonstrate small thin-walled pancreatic cysts or dilated hypoechoic ducts (main pancreatic duct over 5 mm in caliber). Diffuse main duct type has appearances essentially indistinguishable from chronic pancreatitis, with duct dilatation and parenchymal atrophy 5.
Mural nodules and mucin globules may appear hyperechoic, and difficult to separate from adjacent pancreatic parenchyma 6.
They present as single or multiple pancreatic cystic hypodense lesions. Dilatation of the main duct over 5 mm is concerning for the main type IPMN. The communication with the pancreatic ducts, particularly the side branch lesions, may be difficult to demonstrate on CT. They do not calcify.
Both a dedicated pancreatic CT protocol and pancreatic MRI/MRCP have been reported as having similar accuracy in the characterization of the pancreatic cystic lesions 16, but most recent guidelines recommend MRI as the modality of choice for IPMN follow-up.
MRI studies, particularly MRCP, have largely replaced CT in the imaging workup of these lesions.
main duct IPMN (with dilatation of the main duct >5 mm)
either segment of the pancreatic duct (or the entire duct) are dilated and filled with low density (mucin thus water signal) material
overlying pancreatic parenchyma may be thinned
if proximal, the distal pancreatic duct may be dilated without direct involvement (cystic neoplasms can have a similar appearance)
solid mural nodules are concerning for malignant transformation, particularly if enhancing following administration of contrast
occasionally mucinous material can be seen to bulge out of a dilated ampulla of Vater (uncommon but essentially pathognomonic)
mucin globules do not enhance and lie dependently within the duct
branch duct IPMN
the majority of the gland is normal in appearance, except for a single or multiple side branches demonstrating marked dilatation
cystic mass-like appearance which often mimics cystic tumors of the pancreas
its appearance has been termed a bunch of grapes
microcystic variety has appearances similar to serous cystadenomas, but again communication with the main pancreatic duct is the key to the correct diagnosis
appears like an advanced branch duct IPMN with main pancreatic duct dilatation over 5 mm
See the Fukuoka consensus guidelines / Tanaka criteria for further details.
Treatment and prognosis
Although generally indolent, malignant degeneration does occur, with direct invasion into adjacent organs or more frequently dissemination in the peritoneal cavity (pseudomyxoma peritonei).
Current consensus criteria recommend resection for main duct IPMNs and varying treatment of branch duct IPMNs, ranging from resection to surveillance, depending on high-risk stigmata and worrisome features (see: Fukuoka consensus guidelines / Tanaka criteria). Patient co-morbidities and wishes clearly have a major impact on the decision to operate.
If the lesion is proximal (either segmental main duct or branch type) then a Whipple procedure may be performed. If distal then a partial pancreatectomy suffices. Complete resection is curative.
General imaging differential considerations include:
difficult to distinguish from main duct type on account of dilated duct 5
should not appear to communicate with the main pancreatic duct
should not appear to communicate with the main pancreatic duct
appear similar to microcystic branch type IPMN
30-40% have central calcification
The radiological report has to be clear regarding imaging worrisome features of these lesions that may guide further surgical intervention:
main duct IPMN
main pancreatic duct over 5 mm
presence of contrast-enhancing components
branch duct IPMN
main pancreatic duct over 5 mm
cyst diameter ≥3 cm
presence of a contrast-enhancing mural nodule ≥5 mm 16
presence of solid mass 16
thickened and enhancing cyst wall
growth rate ≥5 mm/year
Clinical features to guide surgery may also include:
- 1. Weissleder R, Wittenberg J, Harisinghani MG. Primer of diagnostic imaging. Mosby Inc. (2003) ISBN:0323023282. Read it at Google Books - Find it at Amazon
- 2. Kawamoto S, Horton KM, Lawler LP et-al. Intraductal papillary mucinous neoplasm of the pancreas: can benign lesions be differentiated from malignant lesions with multidetector CT? Radiographics. 25 (6): 1451-68. doi:10.1148/rg.256055036 - Pubmed citation
- 3. Sahani DV, Kadavigere R, Saokar A et-al. Cystic pancreatic lesions: a simple imaging-based classification system for guiding management. Radiographics. 25 (6): 1471-84. doi:10.1148/rg.256045161 - Pubmed citation
- 4. Dähnert W. Radiology review manual. Lippincott Williams & Wilkins. (2003) ISBN:0781738954. Read it at Google Books - Find it at Amazon
- 5. Procacci C, Megibow AJ, Carbognin G et-al. Intraductal papillary mucinous tumor of the pancreas: a pictorial essay. Radiographics. 19 (6): 1447-63. Radiographics (full text) - Pubmed citation
- 6. Silas AM, Morrin MM, Raptopoulos V et-al. Intraductal papillary mucinous tumors of the pancreas. AJR Am J Roentgenol. 2001;176 (1): 179-85. AJR Am J Roentgenol (full text) - Pubmed citation
- 7. Tanaka M, Fernández-del Castillo C, Adsay V et-al. International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas. Pancreatology. 2012;12 (3): 183-97. doi:10.1016/j.pan.2012.04.004 - Pubmed citation
- 8. Roch AM, Parikh JA, Al-Haddad MA et-al. Abnormal serum pancreatic enzymes, but not pancreatitis, are associated with an increased risk of malignancy in patients with intraductal papillary mucinous neoplasms. Surgery. 2014;156 (4): 923-9. doi:10.1016/j.surg.2014.07.010 - Pubmed citation
- 9. Lubezky N, Ben-Haim M, Nakache R et-al. Clinical presentation can predict disease course in patients with intraductal papillary mucinous neoplasm of the pancreas. World J Surg. 2010;34 (1): 126-32. doi:10.1007/s00268-009-0269-y - Pubmed citation
- 10. Salvia R, Fernández-del Castillo C, Bassi C et-al. Main-duct intraductal papillary mucinous neoplasms of the pancreas: clinical predictors of malignancy and long-term survival following resection. Ann. Surg. 2004;239 (5): 678-85. Free text at pubmed - Pubmed citation
- 11. Ohno E, Itoh A, Kawashima H et-al. Malignant transformation of branch duct-type intraductal papillary mucinous neoplasms of the pancreas based on contrast-enhanced endoscopic ultrasonography morphological changes: focus on malignant transformation of intraductal papillary mucinous neoplasm itself. Pancreas. 2012;41 (6): 855-62. doi:10.1097/MPA.0b013e3182480c44 - Pubmed citation
- 12. Tanaka M, Fernández-del Castillo C, Adsay V et-al. International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas. Pancreatology. 2012;12 (3): 183-97. doi:10.1016/j.pan.2012.04.004 - Pubmed citation
- 13. Castelli F, Bosetti D, Negrelli R et-al. Multifocal branch-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas: magnetic resonance (MR) imaging pattern and evolution over time. Radiol Med. 2013;118 (6): 917-29. doi:10.1007/s11547-013-0945-8 - Pubmed citation
- 14. Strauss A, Birdsey M, Fritz S et-al. Intraductal papillary mucinous neoplasms of the pancreas: radiological predictors of malignant transformation and the introduction of bile duct dilation to current guidelines. Br J Radiol. 2016;89 (1061): 20150853. doi:10.1259/bjr.20150853 - Pubmed citation
- 15. Machado NO, Al Qadhi H, Al Wahibi K. Intraductal Papillary Mucinous Neoplasm of Pancreas. (2015) North American journal of medical sciences. 7 (5): 160-75. doi:10.4103/1947-2714.157477 - Pubmed
- 16. European Evidence-Based Guidelines on Pancreatic Cystic Neoplasms. Gut. 2018;67(5):789-804. doi:10.1136/gutjnl-2018-316027 - Pubmed
- 17. Wang W, Chai L, Zhu N, Wang Q, Zhou Y, Chai W. Clinical Significance of Pancreatic Calcifications: A 15-Year Single-Center Observational Study. Eur J Med Res. 2022;27(1):99. doi:10.1186/s40001-022-00725-9 - Pubmed
- 18. Liang W, Tian W, Wang Y et al. Classification Prediction of Pancreatic Cystic Neoplasms Based on Radiomics Deep Learning Models. BMC Cancer. 2022;22(1):1237. doi:10.1186/s12885-022-10273-4 - Pubmed
- 19. Tsujimae M, Masuda A, Shiomi H et al. Significance of Pancreatic Calcification on Preoperative Computed Tomography of Intraductal Papillary Mucinous Neoplasms. J Gastroenterol Hepatol. 2019;34(9):1648-55. doi:10.1111/jgh.14732 - Pubmed
- 20. Gupta R, Mortelé K, Tatli S et al. Pancreatic Intraductal Papillary Mucinous Neoplasms: Role of CT in Predicting Pathologic Subtypes. AJR Am J Roentgenol. 2008;191(5):1458-64. doi:10.2214/ajr.07.3302 - Pubmed
- 21. Perez-Johnston R, Narin O, Mino-Kenudson M et al. Frequency and Significance of Calcification in IPMN. Pancreatology. 2013;13(1):43-7. doi:10.1016/j.pan.2012.11.306 - Pubmed