Intraductal Neoplasms of the Pancreas

Abstract

AbstractHere described are definitions, epidemiology, etiology, clinical features, radiology, pathology, and treatment and prognosis of intraductal neoplasms of the pancreas, namely, intraductal papillary mucinous neoplasms (IPMNs), intraductal oncocytic papillary neoplasms (IOPNs), and intraductal tubulopapillary neoplasms (ITPNs). IPMNs are grossly visible intraductal epithelial neoplasms of mucin-producing cells. IPMNs are fairly common without known etiologic factors. Imaging studies show cystically dilated ducts involving branch ducts, the main duct, or the both of ducts. Microscopically, the neoplastic cells grow in papillae with various atypical degree ranging from low-grade to high-grade. The papillae show various morphologic features with expression of characteristic mucin proteins, which are classified into gastric, intestinal, and pancreatobiliary types. Mutations in KRAS and GNAS are frequently found. IPMNs often become invasive, which show adenocarcinoma with ductal or mucinous elements. Disease-specific survivals of patients with surgically resected IPMNs are fairly good in low-grade IPMNs, modest in high-grade IPMNs, however, poor in invasive IPMNs. IOPNs show cystically dilated mucinous ducts with arborizing papillae consist of eosinophilic cells. IOPN is a rare tumor with an average age of patients <65 years. Imaging studies of IOPNs show the same feature as those of IPMNs. Pathologically, IOPNs show high-grade atypia occasionally with invasive elements. IOPNs often harbor fusion genes of ATP1B1-PRKACB, DNAJB1-PRKACA, and ATP1B1-PRKACA. Disease-specific survival rates of patients with surgically resected IOPNs are reported to be 84% for 5-year and 73% for 10-year. ITPNs are intraductal, grossly visible solid neoplasms arising in the MPD or its branches. ITPN is a rare tumor. Imaging studies show characteristic features called the two-tone duct sign and the cork-in-wine bottle sign. Pathologically, ITPNs show packed tubulopaillary glands consist of cuboidal cells with enlarged atypical nuclei and no visible mucin in cytoplasm. ITPNs often harbor mutations in PIK3CA, KMT2C, KMT2D, and BAP. ITPNs are often with invasion, and such cases show poor prognosis.KeywordsIntraductal papillary mucinous neoplasmIntraductal oncocytic neoplasmIntraductal tubulopapillary neoplasmLow-gradeHigh-gradeGNASPRKACAPRKACB