Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Abstract

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

Analysis of Progression Time in Pancreatic Cancer including Carcinoma In Situ Based on Magnetic Resonance Cholangiopancreatography Findings

“…This definition, based on MRCP-detected MPD stenosis, facilitated a more accurate evaluation of the time to progression of PCs. However, it should be noted that a definition of first-time detection of MPD stenosis without tumor lesion based on the appearance of MPD stenosis may not be adequate because PCs also arise from the branch pancreatic duct [20]. Furthermore, a genetic and experimental study suggested that transformation of high-grade PanIN into invasive PC required a time period ranging from 3 to 5 years [5].…”

Diagnostic Strategy of Early Stage Pancreatic Cancer via Clinical Predictor Assessment: Clinical Indicators, Risk Factors and Imaging Findings

“…On the other hand, risk factors included sporadic family history of pancreatic cancer, familial pancreatic cancer, hereditary pancreatic cancer syndrome/hereditary pancreatitis, DM, chronic pancreatitis, heavy alcohol consumption, smoking history, and obesity [ 5 , 21 , 22 , 23 , 24 ]. Imaging findings included the tumor itself and indirect imaging findings (MPD dilation, pancreatic cyst, and IPMN) [ 11 , 14 , 16 , 17 , 25 , 26 , 27 , 28 , 29 ].…”

“…These factors have been suggested as suggestive of early stage PDAC detection in many guidelines and reviews [ 5 , 11 , 14 , 21 , 22 , 24 ]. These three new categories and previously reported percentage of each factor in patients with stage 0–Ⅰ PDAC is shown in Figure 1 and Table 1 [ 15 , 26 ].…”

“…However, imaging findings are only clarified when various imaging examinations are performed. In addition, only approximately 30% of early stage PDAC is undetectable as a tumor using various imaging modalities [ 4 , 13 , 14 , 15 ]. Therefore, indirect imaging findings, such as main pancreatic duct (MPD) dilation or pancreatic cysts, including intraductal mucinous cystic neoplasm (IPMN), are important diagnostic signs [ 13 , 14 , 16 , 17 , 18 ].…”

“…In addition, only approximately 30% of early stage PDAC is undetectable as a tumor using various imaging modalities [ 4 , 13 , 14 , 15 ]. Therefore, indirect imaging findings, such as main pancreatic duct (MPD) dilation or pancreatic cysts, including intraductal mucinous cystic neoplasm (IPMN), are important diagnostic signs [ 13 , 14 , 16 , 17 , 18 ]. Realistically, examining all individuals for factors associated with PDAC in detail is difficult, and not all of them can be examined by imaging modalities.…”