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  • Surgical Pathology Criteria

    Intraductal Papillary Mucinous Neoplasm of the Pancreas


    • Grossly and/or radiographically visible pancreatic intraductal mucinous epithelial proliferation that forms papillary projections

    Alternate/Historical Names

    • IPMN

    Diagnostic Criteria

    • Grossly visible lesion
      • Involves main duct or branch ducts
      • Variable duct dilation
        • Usually >1 cm diameter
    • Predominantly papillary
      • Rarely flat
    • Four types recognized
      • Gastric type lined by tall columnar foveolar type cells
        • Small basal nuclei
        • Scattered goblet cells may be seen
        • Usually seen in IPMN involving branch ducts
      • Intestinal type lined by columnar cells with apical mucin
        • Pseudostratified elongated nuclei
        • Goblet cells may predominate
        • Usually seen in IPMN involviing main duct
      • Pancreatobiliary type lined by cuboidal cells with amphophilic cytoplasm
        • Round hyperchromatic nuclei
      • Oncocytic type lined by cells with abundant eosinophilic granular cytoplasm
    • Noninvasive
    • Varying degrees of cytologic atypia and architectural complexity
    • IPMN associated with invasive carcinoma
      • Up to 40% of IPMN associated with invasive carcinoma
      • Invasive carcinoma most often associated with IPMN carcinoma-in-situ grade
      • 60% invasive ductal carcinoma
      • 30% invasive colloid carcinoma
        • >80% mucin pools containing neoplastic epithelial cells
      • 5-10% invasive anaplastic carcinoma
      • Entire lesion should be submitted to evaluate for invasion

    Reetesh Pai MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting/updates: 1/1/07, 1/2/12

    Supplemental studies


    • MUC2 and CDX2 may be positive

    Differential Diagnosis

    Intraductal Papillary Mucinous Neoplasm Mucinous Cystic Neoplasm of the Pancreas
    Usually over age 50 Usually under age 50
    Male>female Nearly all female
    Involves segments of ducts Does not communicate with ducts
    Multiple adjacent cystic spaces If multilocular, usually many smaller cysts within a circumscribed larger cyst
    Extensive papillae formation Minimal papillae
    No ovarian type stroma Ovarian type stroma
    May be associated with colloid carcinoma No association with colloid carcinoma

    Intraductal Papillary Mucinous Neoplasm PanIN
    Usually clinically detectable Usually not clinically detectable
    Grossly visible Not grossly visible
    May have well formed papillae No well formed papillae
    May be associated with colloid carcinoma No association with colloid carcinoma
    MUC2 or CDX2 may be positive MUC2 and CDX2 negative


    • About 5% risk of developing invasive carcinoma in noninvasive cases even if margins negative
      • Unclear risk if margins involved
    • Standard of care is conservative resection of gross disease without depleting pancreatic reserves

    Grading / Staging / Report

    • Grading
      • IPMN adenoma grade
        • Tall columnar cells
          • Basal nucleli
          • Abundant supranuclear mucin
        • Usually gastric type epithelium
        • Involves branch ducts more than main duct
      • IPMN borderline grade
        • Increased architectural complexity
        • Maintains identifiable stroma cores in papillae
        • Moderate loss of polarity and pseudostratification
        • Moderate nuclear enlargement and hyperchromasia
        • Usually intestinal or pancreato-biliary epithelium
        • Commonly involves main duct
      • IPMN carcinoma-in-situ grade
        • Cribriform pattern
        • Budding of small clusters of epithelial cells into the lumen
        • Frequent lumenal necrosis
        • Severe loss of nuclear polarity
        • Celllular pleomorphism
        • Lumenal mitotic activity
        • Intracytoplasmic mucin may be depleted
        • Usually lined by intestinal or pancreatobiliary epithelium
        • Commonly involves main duct
    • Staging is not relevant unless invasive carcinoma is present
    • Report
      • Grade
      • Presence or absence of invasive carcinoma
        • Give type and size
      • Margin status for both invasive carcinoma and IPMN
      • For noninvasive lesions
        • Note that there appears to be about a 5% risk of developing carcinoma even if margins negative
        • Suggest clinical followup


    Cystic Pancreatic Lesions

    Mucinous Pancreatic Lesions


    • Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010.
    • Hruban RH, Takaori K, Klimstra DS, Adsay NV, Albores-Saavedra J, Biankin AV, Biankin SA, Compton C, Fukushima N, Furukawa T, Goggins M, Kato Y, Kloppel G, Longnecker DS, Luttges J, Maitra A, Offerhaus GJ, Shimizu M, Yonezawa S. An illustrated consensus on the classification of pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasms. Am J Surg Pathol. 2004 Aug;28(8):977-87.
    • Maitra A, Fukushima N, Takaori K, Hruban RH. Precursors to invasive pancreatic cancer. Adv Anat Pathol. 2005 Mar;12(2):81-91.
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