Does preoperative cross-sectional imaging accurately predict main duct involvement in intraductal papillary mucinous neoplasm?

Lower Interobserver Reliability for Nondimensional Intracystic Features Among Abdominal Radiologists for Characterizing Intraductal Papillary Mucinous Neoplasms Using Magnetic Resonance Imaging

OBJECTIVES

Current guidelines recommend magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) for risk stratification of intraductal papillary mucinous neoplasms (IPMNs). We assessed the interobserver agreement among radiologists in evaluating and risk stratifying IPMNs.

METHODS

This single-center study evaluated 30 patients with IPMNs who had undergone MRI/MRCP, endoscopic ultrasound, and/or surgical resection. Six abdominal radiologists evaluated the MRI/MRCPs to document multiple parameters. The analysis applied Landis and Koch κ interpretation for categorical variables and intraclass correlation coefficient (r) for continuous variables.

RESULTS

Radiologists demonstrated almost perfect agreement for location (κ = 0.81, 95% confidence interval [CI], 0.74-0.87), size (r = 0.95; 95% CI, 0.89-0.98), and main pancreatic duct diameter (r = 0.98; 95% CI, 0.96-0.99). Substantial agreement was observed for communication with the main pancreatic duct (κ = 0.66; 95% CI, 0.57-0.75) and classification of IPMN subtype (κ = 0.77; 95% CI, 0.67-0.86). Presence of intracystic nodules (κ = 0.31; 95% CI, 0.21-0.42) and wall thickening (κ = 0.09; 95% CI, -0.01 to 0.18) reached only fair and slight agreement, respectively.

CONCLUSIONS

Although MRI/MRCP is excellent in the evaluation of spatial aspects, there is lower reliability for nondimensional characteristics of IPMNs. These data support guideline-recommended complementary evaluation of IPMNs with MRI/MRCP and endoscopic ultrasound.

Intraductal Papillary Mucinous Neoplasms: Have IAP Consensus Guidelines Changed our Approach?: Results from a Multi-institutional Study

OBJECTIVE

To evaluate the influence of consensus guidelines on the management of intraductal papillary mucinous neoplasms (IPMN) and the subsequent changes in pathologic outcomes.

BACKGROUND

Over time, multiple guidelines have been developed to identify high-risk IPMN. We hypothesized that the development and implementation of guidelines should have increased the percentage of resected IPMN with high-risk disease.

METHODS

Memorial Sloan-Kettering (MSK), Johns Hopkins (JH), and Massachusetts General Hospital (MGH) databases were queried for resected IPMN (2000-2015). Patients were categorized into main-duct (MD-IPMN) versus branch-duct (BD-IPMN). Guideline-specific radiographic/endoscopic features were recorded. High-risk disease was defined as high-grade dysplasia/carcinoma. Fisher's exact test was used to detect differences between institutions. Logistic regression evaluated differences between time-points [preguidelines (pre-GL, before 2006), Sendai (SCG, 2006-2012), Fukuoka (FCG, after 2012)].

RESULTS

The study included 1210 patients. The percentage of BD-IPMN with ≥1 high-risk radiographic feature differed between centers (MSK 69%, JH 60%, MGH 45%; P < 0.001). In MD-IPMN cohort, the presence of radiographic features such as solid component and main pancreatic duct diameter ≥10 mm also differed (solid component: MSK 38%, JH 30%, MGH 18%; P < 0.001; duct ≥10 mm: MSK 49%, JH 32%, MGH 44%; P < 0.001). The percentage of high-risk disease on pathology, however, was similar between institutions (BD-IPMN: P = 0.36, MD-IPMN: P = 0.48). During the study period, the percentage of BD-IPMN resected with ≥1 high-risk feature increased (52% pre-GL vs 67% FCG; P = 0.005), whereas the percentage of high-risk disease decreased (pre-GL vs FCG: 30% vs 20%). For MD-IPMN, there was not a clear trend towards guideline adherence, and the rate of high-risk disease was similar over the time (pre-GL vs FCG: 69% vs 67%; P = 0.63).

CONCLUSION

Surgical management of IPMN based on radiographic criteria is variable between institutions, with similar percentages of high-risk disease. Over the 15-year study period, the rate of BD-IPMN resected with high-risk radiographic features increased; however, the rate of high-risk disease decreased. Better predictors are needed.

Assessment of Malignancy Potential in Intraductal Papillary Mucinous Neoplasms of the Pancreas on MDCT

RATIONALE AND OBJECTIVE

To assess the malignancy potential of intraduct papillary mucinous neoplasms (IPMNs) on multidetector-row computerized tomography according to the 2012 International Consensus Guidelines (ICG).

MATERIALS AND METHODS

This study retrospectively collected IPMNs confirmed by surgery from 2016 to 2019. The imaging findings of IPMNs were analyzed. IPMNs were classified as malignancy in the presence of high-grade dysplasia or invasive carcinoma and began in the presence of low- and intermediate-grade dysplasia.

RESULTS

A total of 207 patients (mean age: 63.7 ± 7.9 years) were included, and the prevalence of malignancy was 28.0% (58 of 207). According to the 2012 ICG, the imaging findings of IPMNs were divided into worrisome features (WFs) and high-risk stigmata (HRS). The malignancy of IPMN with only one WF was relatively low (1.4%, 3 of 207). In multivariate regression analyses, the independent factors of IPMNs were enhanced mural nodule ≥5 mm (odds ratio [OR] = 19.5, 95% confidence interval [CI] 6.8-55.4), abrupt change in the main pancreatic duct caliber with distal pancreatic atrophy (OR = 4.6, 95%CI 1.67-12.71), and thickened enhanced cyst walls (OR = 2.9, 95%CI 1.1-8.2). When the presence of more than two WFs or HRS (score ≥ 3) was regarded as indicating the malignancy potential of IPMNs on multidetector-row computerized tomography, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 89.7%, 75.8%, 79.7%, 59.1%, and 95.0%, respectively.

CONCLUSION

According to the ICG in 2012, patients with IPMNs with only one WF have a low risk for malignancy, and the presence of at least two WFs or any HRS (score ≥3) suggests malignant IPMNs.

Ductal Dilatation of ≥5 mm in Intraductal Papillary Mucinous Neoplasm Should Trigger the Consideration for Pancreatectomy: A Meta-Analysis and Systematic Review of Resected Cases

Simple Summary

Intraductal papillary mucinous neoplasms (IPMN) are common but difficult to manage since accurate tools for diagnosing malignancy are unavailable. This study evaluates the diagnostic value of main pancreatic duct (MPD) diameter for detecting IPMN malignancy, using a meta-analysis of published data. The result suggests that malignancy is highly prevalent in IPMN with ductal dilatation of >5 mm.

Abstract

Intraductal papillary mucinous neoplasms (IPMN) are common but difficult to manage since accurate tools for diagnosing malignancy are unavailable. This study tests the diagnostic value of the main pancreatic duct (MPD) diameter for detecting IPMN malignancy using a meta-analysis of published data of resected IPMNs. Collected from a comprehensive literature search, the articles included in this analysis must report malignancy cases (high-grade dysplasia (HGD) and invasive carcinoma (IC)) and MPD diameter so that two MPD cut-offs could be created. The sensitivity, specificity, and odds ratios of the two cutoffs for predicting malignancy were calculated. A review of 1493 articles yielded 20 retrospective studies with 3982 resected cases. A cutoff of ≥5 mm is more sensitive than the ≥10 mm cutoff and has pooled sensitivity of 72.20% and 75.60% for classification of HGD and IC, respectively. Both MPD cutoffs of ≥5 mm and ≥10 mm were associated with malignancy (OR = 4.36 (95% CI: 2.82, 6.75) vs. OR = 3.18 (95% CI: 2.25, 4.49), respectively). The odds of HGD and IC for patients with MPD ≥5 mm were 5.66 (95% CI: 3.02, 10.62) and 7.40 (95% CI: 4.95, 11.06), respectively. OR of HGD and IC for MPD ≥10 mm cutoff were 4.36 (95% CI: 3.20, 5.93) and 4.75 (95% CI: 2.39, 9.45), respectively. IPMN with MPD of >5 mm could very likely be malignant. In selected IPMN patients, pancreatectomy should be considered when MPD is >5 mm.

Intraductal papillary mucinous neoplasm of the pancreas: Cytomorphology, imaging, molecular profile, and prognosis

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) constitutes up to 20% of all pancreatic resections, and has been increasing in recent years. Histomorphological findings of IPMN are well established; however, there are not many published papers regarding the cytological findings of IPMN on fine needle aspiration (FNA) specimens. We review the cytomorphological features, molecular profile, imaging findings, and prognosis of IPMN.

METHODS

The English literature was thoroughly searched with key phrases containing IPMN.

OBSERVATIONS

IPMN is a rare entity, affecting men and women equally and is usually diagnosed at the age of 60-70 years. The characteristic imaging features include a cystic lesion with associated dilatation of the main or branch pancreatic duct, and atrophy of surrounding pancreatic parenchyma. Cytomorphological features of IPMN include papillary fragments of mucinous epithelium in a background of abundant thick extracellular mucin, a hallmark feature. IPMNs should be evaluated for high-grade dysplasia, which manifests with nuclear atypia, nuclear moulding, prominent nucleoli, nuclear irregularity, and cellular crowding. Molecular profiling of IPMN along with carcinoembryonic antigen and amylase levels is useful in predicting malignancy or high-grade dysplasia arising in IPMN. Overall, the prognosis of IPMN is excellent except in those cases with high-grade dysplasia and malignant transformation. Postoperative surveillance is required for resected IPMNs.

CONCLUSION

IPMN requires a multidisciplinary approach for management. Cytomorphological findings of IPMN on FNA, in conjunction with tumour markers in pancreatic fluid cytology and imaging findings, are of paramount importance in clinical decision-making for IPMN.

Nomogram for the Prediction of High-Grade Dysplasia and Invasive Carcinoma in Patients With Intraductal Papillary Mucinous Neoplasms of the Pancreas Based on Variables of Noninvasive Examination

Intraductal papillary mucinous neoplasms (IPMNs) are a heterogeneous group of neoplasms and represent the most common identifiable precursor lesions of pancreatic cancer. Clinical decision-making of the risk for malignant disease, including high-grade dysplasia and invasive carcinoma, is challenging. Moreover, discordance on the indication for resection exists between the contemporary guidelines. Furthermore, most of the current nomogram models for predicting malignant disease depend on endoscopic ultrasonography to evaluate the precise size of mural nodules. Thus, this study aimed to propose a model to predict malignant disease using variables from a noninvasive examination. We evaluated patients who underwent resection of pathologically confirmed IPMNs between November 2010 and December 2018 and had preoperative clinical data available for review. Based on binary multivariable logistic regression analysis, we devised a nomogram model to predict malignant IPMNs. The area under the receiver operating characteristics curve (AUC) was used to evaluate the discrimination power of the model. Of the 333 patients who underwent resection of IPMNs, 198 (59.5%) had benign and 135 (40.5%) had malignant IPMNs. Multivariable logistic regression analysis showed that cyst size, cyst location, cyst wall enhancement, multicystic lesion, diameter of main pancreatic duct, neutrophil-to-lymphocyte ratio, serum carbohydrate antigen 19-9, and carcinoembryonic antigen were significantly associated with malignancy. The nomogram, constructed based on these variables, showed excellent discrimination power with an AUC of 0.859 (95% CI: 0.818–0.900, P < 0.001). In conclusion, we have developed a nomogram consisting of a combination of cross-sectional imaging features and blood markers, variables that can readily be obtained by noninvasive examinations during the surveillance period, which can distinguish benign from malignant IPMNs. Nevertheless, external validation is warranted.

Can the location of the mural nodule indicate benign or malignant in branch duct-type intraductal papillary mucinous neoplasm of the pancreas?

BACKGROUND/OBJECTIVES

Intraductal papillary mucinous neoplasms (IPMNs) are classified into main duct (MD)-type IPMNs, branch duct (BD)-type IPMNs, and mixed type IPMNs. While MD-type IPMN has a high risk of malignancy and should therefore be considered for resection if the patient is fit, BD-type IPMN needs to be carefully judged for surgical indication. The decision to resect BD-type IPMN is often based on international consensus Fukuoka guidelines 2017, but further investigation is required. In this study, we focused on whether the location of the mural nodule (MN) could be an indicator of malignancy.

METHODS

We enrolled 17 cases who had been diagnosed BD-type IPMNs which were surgically resected from January 2016 to December 2019. These cases were classified into benign and malignant group. Subsequently, a clinicopathological study was conducted based on the localization of MN (MN-central type or MN-peripheral type).

RESULTS

Although MN was found in 57% (4/11) in the benign group, 88% (7/8) was noted in the malignant group, indicating the presence of MN to be more common in the malignant group. Those with MN consisted of 6 cases of MN-central type and 5 cases of MN-peripheral type. All cases of central type were malignant compared to only one case of the peripheral group being confirmed on histology as cancer.

CONCLUSION

BD-IPMN with central mural nodule should be considered high risk for malignancy.

Can contrast-enhanced harmonic endoscopic ultrasonography accurately diagnose main pancreatic duct involvement in intraductal papillary mucinous neoplasms?

BACKGROUND

Main pancreatic duct (MPD) involvement in branch duct-type intraductal papillary mucinous neoplasms (BD-IPMNs) is a high risk finding for malignant IPMNs. However, discrepancies exist in the identification of MPD involvement between imaging findings and pathological diagnosis. The purpose of this study was to evaluate the diagnostic accuracy of preoperative assessment of MPD involvement in IPMNs using contrast-enhanced harmonic endoscopic ultrasound (CH-EUS).

METHODS

This study involved 166 consecutive patients with BD-IPMNs who underwent surgical resection. CH-EUS was used to evaluate the MPD involvement according to the presence of mural nodules (MN) that advanced into the MPD or involved the MPD. The CH-EUS findings were compared with the pathological findings. Additionally, we analyzed the risk factors for malignant BD-IPMNs using multivariate analysis.

RESULTS

A total of 77, 51, and 38 patients were pathologically diagnosed with low-grade or intermediate-grade dysplasia, high-grade dysplasia and invasive IPMNs, respectively. MPD involvement was diagnosed using CH-EUS (MPD-inv.-EUS) in 90 (54.2%) patients with a sensitivity, specificity and accuracy of 83.5%, 87.0% and 84.9%, respectively. The malignancy rate in patients with MPD-inv.-EUS was 71.6% (63/90). Multivariate logistic regression analysis showed that MPD-inv.-EUS (OR, 3.61; 95% CI:1.45-8.98), age (OR, 5.70; 95% CI: 1.47-22.2), cyst size (OR, 2.45; 95% CI:1.04-5.78) and MN size (OR, 7.05; 95% CI:2.48-20.0) were significant for malignant BD-IPMNs.

CONCLUSIONS

MPD-inv.-EUS accurately represents the pathological involvement of IPMN and may be a useful predictor of malignant BD-IPMNs.

Pancreatic Nerve Sheath Tumors: a Single Institutional Series and Systematic Review of the Literature

INTRODUCTION

Improvement in imaging has resulted in frequent diagnosis of benign and premalignant pancreatic tumors. Pancreatic nerve sheath (PNS) tumors are one of the rarest pancreatic tumors. Literature on PNS is limited and their biology is poorly understood. Here, we report the largest series of PNS tumors to date and review the literature to evaluate the current data available on PNS tumors.

METHODS

An institutional database was used to identify patients who underwent resection for PNS tumors. Clinicopathological characteristics and outcomes of these patients were reported. Furthermore, a review of literature was performed.

RESULTS

From January 1994 through December 2016, seven patients underwent resection for PNS tumors. The median age was 57.7 years (IQR, 44.9-61.9) and the sex was approximately equally distributed (male = 4; 57.1%). Three (42.9%) patients were diagnosed incidentally and six (85.7%) were misdiagnosed as having other pancreatic tumors. The median tumor size was 2.1 (IQR 1.8-3.0) cm and six (85.7%) had no nodal disease. At a median follow-up of 15.5 (IQR 13.7-49.3) months, six patients were alive without evidence of disease and one patient was lost to follow-up. The literature review identified 49 studies reporting 54 patients with PNS tumors. Forty-six were misdiagnosed as having other pancreatic tumors. The median tumor size was 3.6 (range 1-20) cm, nodal disease was present in six patients (22.2%), and no patient had distant metastatic disease. At the time of last follow-up, all patients were free of disease.

CONCLUSION

This is the largest single institution series on PNS tumors reported to date. These tumors are rare and are often misdiagnosed, given their radiological characteristics. PNS tumors have a benign course of disease and surgical resection results in favorable long-term outcomes.

Diagnosis and Surveillance of Incidental Pancreatic Cystic Lesions: 2017 Consensus Recommendations of the Korean Society of Abdominal Radiology

The occurrence of incidentally detected pancreatic cystic lesions (PCLs) is continuously increasing. Radiologic examinations including computed tomography and magnetic resonance imaging with magnetic resonance cholangiopancreatography have been widely used as the main diagnostic and surveillance methods for patients with incidental PCLs. Although most incidentally detected PCLs are considered benign, they have the potential to become malignant. Currently, we have several guidelines for the management of incidental PCLs. However, there is still debate over proper management, in terms of accurate diagnosis, optimal follow-up interval, and imaging tools. Because imaging studies play a crucial role in the management of incidental PCLs, the 2017 consensus recommendations of the Korean Society of Abdominal Radiology for the diagnosis and surveillance of incidental PCLs approved 11 out of 16 recommendations. Although several challenges remain in terms of optimization and standardization, these consensus recommendations might serve as useful tools to provide a more standardized approach and to optimize care of patients with incidental PCLs.

Systematic review of the clinical utility and validity of the Sendai and Fukuoka Consensus Guidelines for the management of intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

This systematic review was performed to assess the clinical utility of the Sendai Consensus Guidelines (SCG) and Fukuoka Consensus Guidelines (FCG) for intraductal papillary mucinous neoplasm (IPMN).

METHODS

A computerized search of PubMed was performed to identify all the studies which evaluated the SCG and FCG in surgically resected, histologically confirmed IPMNs.

RESULTS

Ten studies evaluating the FCG, 8 evaluating the SCG and 4 evaluating both guidelines were included. In 14 studies evaluating the FCG, out of a total of 2498 neoplasms, 849 were malignant and 1649 were benign neoplasms. Pooled analysis showed that 751 of 1801 (42%) FCG+ve neoplasms were malignant and 599 neoplasms of 697 (86%) FCG-ve neoplasms were benign. PPV of the high risk and worrisome risk groups were 465/986 (47%) and 239/520 (46%) respectively. In 12 studies evaluating the SCG, 1234 neoplasms were analyzed of which 388 (31%) were malignant and 846 (69%) were benign. Pooled analysis demonstrated that 265 of 802 (33%) SCG+ve neoplasms were malignant and 238 of 266 SCG-ve (90%) neoplasms were benign.

CONCLUSION

The FCG had a higher positive predictive value (PPV) compared to the SCG. However, the negative predictive value (NPV) of the FCG was slightly lower than that of the SCG. Malignant and even invasive IPMN may be missed according to both guidelines.

Diagnostic Accuracy of Preoperative Imaging for Differentiation of Branch Duct Versus Mixed Duct Intraductal Papillary Mucinous Neoplasms

OBJECTIVE

The aim of this study is to determine the diagnostic accuracy of preoperative evaluation to detect main pancreatic duct involvement in pancreatic cystic lesions thus differentiating mixed intraductal papillary mucinous neoplasm (IPMN) from branch duct (BD)-IPMN.

METHODS

The pathology database of pancreatic resections from 2000 to 2014 was reviewed. Main pancreatic duct-IPMNs and IPMNs with intracystic mass/nodules were excluded. The preoperative test characteristics were analyzed using surgical histopathology as the "gold standard."

RESULTS

Sixty BD-IPMNs and 23 mixed-IPMNs were identified. Mixed-IPMNs were larger (mean [standard deviation], 4.14 [2.9] vs 2.74 [1.9] mm; P = 0.03) and demonstrated frequent high-grade dysplasia/adenocarcinoma (43% vs 12%, P = 0.004) than BD-IPMNs. Endoscopic ultrasound (EUS) (sensitivity, 80%; specificity, 78%; accuracy, 79%) had the best diagnostic accuracy, whereas magnetic resonance imaging (MRI) (sensitivity, 83%; specificity, 63%; accuracy, 68%) had the highest sensitivity for the diagnosis of mixed-IPMN. A combination of EUS and MRI reached maximum sensitivity but with decreased accuracy (sensitivity, 100%; specificity, 64%; accuracy, 67%). The area under the curve for receiver operation curve was 0.71 whereas the optimal cyst size to detect main duct involvement was 3 cm.

CONCLUSIONS

For preoperative evaluation of pancreatic cystic lesions without evidence of intracystic nodules, a combination of MRI and EUS should be considered for improved detection of main duct involvement.

Intraductal Papillary Mucinous Neoplasm of the Pancreas as the Main Focus for Early Detection of Pancreatic Adenocarcinoma

For early detection of pancreatic cancer, interests are now focused on the detection of high-risk individuals to undergo screening examinations. Intraductal papillary mucinous neoplasm (IPMN) is a unique dual precursor of pancreatic cancer, characterized by progression to invasive cancer and the development of pancreatic adenocarcinoma either concomitantly (synchronous occurrence) or even after resection of IPMN (metachronous occurrence). Careful examination and surveillance of patients with IPMN may therefore lead to early detection of pancreatic cancer. By reviewing only reports describing detailed breakdown of the morphological types of IPMN and numbers of patients with noninvasive and invasive carcinoma in each type, the rough frequencies of noninvasive carcinoma in main duct IPMNs and branch duct IPMNs (BD-IPMNs) are 20% and 10%, respectively, and those of invasive carcinoma are 40% and 13%, respectively. Roughly 5% of all patients with IPMN had concomitant adenocarcinoma. The real frequency of carcinoma in BD-IPMNs would be far lower because most patients with small asymptomatic BD-IPMNs do not undergo resection. Intraductal papillary mucinous neoplasm can be the main focus for early detection of pancreatic cancer to achieve favorable prognosis after surgical resection. The optimal protocol for surveillance and method for early detection of pancreatic cancer are to be determined.

Fukuoka-Negative Branch-Duct IPMNs: When to Worry? A Study from the French Surgical Association (AFC)

BACKGROUND

This study analyzed the pathologic findings for patients with Fukuoka-negative branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) who theoretically were eligible for surveillance care with follow-up assessment, but instead underwent resection.

METHODS

From January 2005 to December 2012, 820 patients underwent evaluation for IPMN. At initial staging, 319 patients had BD-IPMN, and 89 of these patients presented with Fukuoka-negative criteria. These 89 patients were included in this study.

RESULTS

Of the 89 patients, 55 (62%) underwent pancreatectomy. After pathologic examination, the ultimate diagnosis was MT-IPMN for 20 (36%) of these patients (the MT group) and BD-IPMN for 35 (64%) of these patients (the BD group). The remaining 34 patients (38%) underwent enucleation. The patients in the MT group were more likely to be male (P = 0.01) and to have a higher rate of recent (< 1 year) diabetes mellitus diagnosis (P = 0.007) than the patients in the BD group. In the multivariate analysis, diabetes mellitus was independently associated with involvement of the main pancreatic duct (P = 0.05). Malignancy was diagnosed for 14 (16%) of the 89 patients. The rate of invasive IPMN was higher in the MT group than in the BD group (20% vs. 0%, P = 0.02). The 5-year overall survival rate was 100% for the BD group and 84% for the MT group (P = 0.02). For the male patients with diabetes mellitus, the rate of malignancy rose to 67%.

CONCLUSIONS

For patients with a diagnosis of Fukuoka-negative BD-IPMN, resection should be considered primarily for male patients with a recent diabetes mellitus diagnosis.

[Branch duct intraductal papillary mucinous neoplasm - surgical approach]

Due to increasing precision of modern imaging modalities, intraductal papillary mucinous neoplasms (IPMN) of the pancreas are found with increasing prevalence. Despite their malignant potential IPMN are often kept under surveillance and are not immediately resected. The 2012 International Consensus Guidelines of Fukuoka have been widely accepted for the management of IPMN. They recommend surgical resection for branch duct IPMN with "high risk stigmata", while branch duct IPMN with "worrisome features" should undergo observation without immediate resection. Consequently, patients with asymptomatic branch duct IPMN and a presumed low malignant potential mostly undergo primary surveillance to avoid surgery-related morbidity and mortality following pancreatic resection; however, with respect to the cumulative risk of malignant transformation over time, surgical resection might also be indicated for patients with branch duct IPMN with "worrisome features". This article discusses the indications for surgery and different options of resection of branch duct IPMN.

Intraductal papillary mucinous neoplasm of the pancreas - epidemiology, risk factors, diagnosis, and management

Intraductal papillary mucinous neoplasm (IPMN) is one of the most common cystic neoplasms of the pancreas. It is a heterogeneous disease and can be divided into ductal types and morphological subtypes. The incidence of IPMN is increasing, likely due to the widespread use of cross-sectional imaging and a growing elderly population. IPMN poses an increasing demand on the health care system. Current guidelines provide indications for surgery and recommendations for surveillance, but management of IPMN is still challenging in routine clinical practice. In this article, we review current knowledge about IPMN and provide future directions for improving diagnosis and management.

Pancreatic Cysts and Guidelines

Pancreatic cysts, especially incidental asymptomatic ones seen on noninvasive imaging such as CT or MR imaging, remain a clinical challenge. The etiology of such cysts may range from benign cysts without any malignant potential such as pancreatic pseudocysts and serous cystadenomas to premalignant or frankly malignant cysts such as mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, cystic degeneration associated with solid tumors such as pancreatic ductal adenocarcinoma or pancreatic endocrine neoplasms, and solid pseudopapillary neoplasms. The clinical challenge in 2017 is to accurately preoperatively diagnose them and their malignant potential before deciding about surgery, surveillance or doing nothing. This review will focus on the currently available clinical guidelines for doing so.

Natural History of Pancreatic Cysts

Pancreatic cystic neoplasms are discovered with increasing frequency. Accurate knowledge of the natural history of cystic neoplasms is crucial to develop useful and cost-effective strategies for surveillance and surgical resection. To date, the natural history of cystic neoplasms is still incomplete due to lack of adequate diagnostic accuracy in the absence of surgical pathology. Nevertheless, current evidence points to risk factors for malignant transformation to help clinical management. New biomarkers that accurately distinguish cyst neoplasms and those most likely to progress to cancer would help clarify the natural history of cystic neoplasms.

Diagnostic performance and imaging features for predicting the malignant potential of intraductal papillary mucinous neoplasm of the pancreas: a comparison of EUS, contrast-enhanced CT and MRI

PURPOSE

To compare diagnostic performance for prediction of malignant potential in IPMNs between EUS, contrast-enhanced CT and MRI.

MATERIALS AND METHODS

76 patients with IPMN (benign = 37, malignant = 39) underwent EUS, contrast-enhanced CT, and MRI. EUS was analyzed based on formal reports and contrast-enhanced CT and MRI were retrospectively analyzed by two radiologists according to the consensus guidelines 2012. Diagnostic performance and imaging features of malignant IPMNs were analyzed using ROC analysis and multivariate analyses.

RESULTS

Diagnostic performance of contrast-enhanced CT (AUC = 0.792 in R1, 0.830 in R2), MRI (AUC = 0.742 in R1, 0.776 in R2), and EUS (AUC = 0.733) for predicting malignant IPMNs were comparable without significant difference (p > 0.05). In multivariable analysis, enhancing solid component in contrast-enhanced CT and MRI and mural nodule in EUS (OR 1.8 in CT, 1.36 in MRI, 1.47 in EUS), MPD diameter ≥ 10 mm (OR 1.3 in CT, 1.4 in MRI, 1.66 in EUS), MPD diameter of 5-9 mm (OR 1.23 in CT, 1.31 in MRI), and thickened septa or wall (OR 1.3 in CT and MRI) were significant variables (p < 0.05). Interobserver agreement of thickened cyst septa or wall (k = 0.579-0.617) and abrupt caliber change of MPD (k = 0.689-0.788) was lower than other variables (k > 0.80).

CONCLUSION

Diagnostic performance of contrast-enhanced CT, MRI, and EUS for predicting malignant IPMNs was comparable with each modalities without significant difference.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Management of patients with pancreatic cystic lesions: A case-based survey

BACKGROUND

Pancreatic cystic lesions (PCL), including intraductal papillary mucinous neoplasia (IPMN), harbor different malignant potential and the optimal management is often challenging. The present study aims to depict the compliance of experts with current consensus guidelines and the accuracy of treatment recommendations stratified by the medical specialty and hospital volume.

METHODS

An international survey was conducted using a set of 10 selected cases of PCL that were presented to a cohort of international experts on pancreatology. All presented cases were surgically resected between 2004 and 2015 and histopathological examination was available. Accuracy of the treatment recommendations was based on the European and international consensus guideline algorithms, and the histopathological result.

RESULTS

The response rate of the survey was 26% (46 of 177 contacted experts), consisting of 70% surgeons and 30% gastroenterologists/oncologists (GI/Onc). In the case of main-duct IPMN (MD-IPMN), surgeons preferred more often the surgical approach in comparison with the GI/Onc (55 versus 44%). The mean accuracy rate based on the European and international consensus guidelines, and the histopathological result, were 71/76/38% (surgeons), and 70/73/34% (GI/Onc), respectively. High-volume centers achieved insignificantly higher accuracy scores with regard to the histopathology. Small branch-duct IPMN with cysts <2 cm and malignant potential were not identified by the guideline algorithms.

CONCLUSION

The survey underlines the complexity of treatment decisions for patients with PCL; less than 40% of the recommendations were in line with the final histopathology in this selected case panel. Experts and consensus guidelines may fail to predict malignant potential in small PCL.

Intraductal Papillary Mucinous Neoplasm of the Pancreas: Current State of the Art and Ongoing Controversies

With the widespread use and advances in radiographic imaging, Intraductal Papillary Mucinous Neoplasms (IPMNs) of the pancreas are identified with increasing frequency. Although many studies have addressed its biology and treatment, true understanding of its natural history continues to elude us. Its malignant potential places careproviders in a clinical dilemma of balancing the morbidity of pancreatectomy against the risk of malignant transformation while under continuous surveillance. Recently, there have been conflicting data published in the literature, generating more uncertainty in the field. In this article, we critically analyze the contrasting consensus guidelines from the International Association of Pancreatology and the American Gastroenterology Association, and address lingering questions and controversies. We also synthesize newly published data in the context of current standard of care, and provide a comprehensive review and recommendations for the clinical diagnosis, treatment, and follow-up strategy in the management of patients with Intraductal Papillary Mucinous Neoplasms.

Validation of the 2012 International Consensus Guidelines Using Computed Tomography and Magnetic Resonance Imaging: Branch Duct and Main Duct Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE

To validate the 2012 guidelines for intraductal papillary mucinous neoplasm (IPMN) of the pancreas and to compare diagnostic performances of computed tomography (CT) and magnetic resonance imaging (MRI) for differentiating malignant from benign IPMN.

BACKGROUND

As IPMN has variable risks of malignancy and management of this entity is closely related to its malignant potential, it is important to predict risks of IPMN malignancy.

METHODS

This retrospective study included 158 patients with surgically confirmed IPMN of the pancreas who underwent both preoperative CT and MRI. Two radiologists evaluated the "high-risk stigmata" and "worrisome features" of the 2012 guidelines for branch duct (BD)-IPMN and main duct (MD)-IPMN. Univariate and multivariable analyses were used to identify significant predictors of malignancy in IPMN. The diagnostic performance was compared between CT and MRI.

RESULTS

Malignant IPMN was seen in 8 of 60 patients (13.3%) with BD-IPMN and 44 of 98 patients (44.9%) with MD-IPMN. Presence of mural nodule was the most important predictor in BD-IPMN and MD-IPMN (odds ratios, 9.2 and 7.6, respectively, P = 0.01 on CT; and odds ratios, 5.7 and 13.3, respectively, P ≤ 0.04 on MRI), whereas mural nodule size and lymphadenopathy were significant only in MD-IPMN (P < 0.05). The diagnostic performance of CT and MRI for significant findings was not statistically different in both types of IPMN (P > 0.34).

CONCLUSIONS

The presence of mural nodule was the most important predictor of malignancy in both types of IPMN. Mural nodule size and lymphadenopathy were also significant predictors in MD-IPMN. Computed tomography and MRI showed similar diagnostic performances for differentiating malignant from benign IPMN.

Distinguishing benign from malignant main duct intraductal papillary mucinous neoplasms of the pancreas by multislice helical computed tomography

Main duct intraductal papillary mucinous neoplasms (MD-IPMNs) of the pancreas are located in the dilated main pancreatic duct and associated with mucin overproduction. They may have a high degree of malignancy and lack specific clinical manifestations. With advantages of thin slice thickness, high resolution, multi-phase dynamic scan and multiple post-processing techniques, multislice helical computed tomography (MSCT) can accurately diagnose and differentiate malignant from benign MD-IPMNs. This paper will review the current advances in differentiating malignant from benign MD-IPMNs by MSCT.

Pancreatic Resection for Side-Branch Intraductal Papillary Mucinous Neoplasm (SB-IPMN): a Contemporary Single-Institution Experience

BACKGROUND

Given the malignant potential of main duct intraductal papillary mucinous neoplasm (M-IPMN), surgical resection is generally indicated. With regard to side-branch intraductal papillary mucinous neoplasm (SB-IPMN), resection vs. observation is a topic of debate. Further review of SB-IPMN is necessary to clarify appropriate management. The primary focus of this project is to determine the incidence of malignant final pathology for patients undergoing surgery for isolated SB-IPMN with non-malignant fine-needle aspiration (FNA) cytology. We also sought to describe the relationship between factors considered in the international consensus guidelines and final pathologic outcome.

METHODS

The study is a retrospective review of all patients who underwent surgical resection for intraductal papillary mucinous neoplasm (IPMN) from 2002 to 2013 at our institution. Patients with a preoperative diagnosis of isolated SB-IPMN and FNA results for non-malignant cytology were selected among this surgical cohort for further analysis of preoperative clinical characteristics and outcomes.

RESULTS

A total of 137 patients undergoing resection for IPMN were identified. Of these, 81 patients (59%) had a component of M-IPMN or invasive disease on FNA, leaving 66 (46%) patients with SB-IPMN and non-malignant cytology. Invasive adenocarcinoma was found in 8/66 (12%) patients and high-grade dysplasia (HGD) in 4/66 (8%) patients. The mean [SD] diameter of benign SB-IPMN was 2.0 cm [1.1] (range 0.3-5.7) vs. that of HGD/invasive disease which was 3.1 cm [1.3] (range 1.5-6.0; P = 0.014). Of the 12 patients found to have HGD or invasive disease, symptoms, mural nodules, and septations were found in 7 (58%), 5 (42%), and 6 (50%), respectively. Tumor staging were as follows: IA (2), IB (2), 2A (4), and 2B (1).

CONCLUSION

With proper selection criteria, SB-IPMN is associated with a low rate of invasive pancreatic ductal adenocarcinoma at the time of resection. Nevertheless, given the demonstrated incidence of malignancy, appropriate operative candidates should undergo resection.

Natural History and Management of Intraductal Papillary Mucinous Neoplasms: Current Evidence

Background

With the use of modern cross-sectional abdominal imaging modalities, an increasing number of cystic pancreatic lesions are identified incidentally. Although there is no pathological diagnosis available in most cases, it is believed that the majority of these lesions display small branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas. Even though a number of large clinical series have been published, many uncertainties remain with regard to this entity of mucinous cystic neoplasms.

Methods

Systematic literature review.

Results

Main-duct (MD) and mixed-type IPMNs harbor a high risk of malignant transformation. It is conceivable that most IPMNs with involvement of the main duct tend to progress to invasive carcinoma over time. Thus, formal oncologic resection is the treatment of choice in surgically fit patients. In contrast, the data regarding BD-IPMN remain equivocal, resulting in conflicting concepts. To date, it is not clear whether and which BD-IPMNs progress to carcinoma and how long this progression takes.

Conclusion

While patients with MD-IPMNs should undergo surgical resection if comorbidities and life expectancy permit this, the management of small BD-IPMNs remains controversial. Population-based studies with long-term follow-up are needed to define which cohort of patients can be observed safely without immediate resection.

Predictors of malignancy in pure branch duct type intraductal papillary mucinous neoplasm of the pancreas: A nationwide multicenter study

BACKGROUND/OBJECTIVES

Prediction of malignancy in patients with BD-IPMNs is critical for the management. The aim of this study was to elucidate predictors of malignancy in patients with 'pure' BD-IPMNs who had a main pancreatic duct (MPD) diameter of ≤5 mm according to the most recent international consensus criteria and in whom MPD involvement was excluded on postoperative histology.

METHODS

We identified 177 patients with 'pure' BD-IPMNs based on preoperative imaging and postoperative histology from 15 tertiary referral centers in Korea. BD-IPMNs with low-grade (n = 72) and moderate-grade (n = 66) dysplasia were grouped as benign and BD-IPMNs with high-grade dysplasia (n = 10) and invasive carcinoma (n = 29) were grouped as malignancy.

RESULTS

On univariate analysis, particular symptoms (jaundice and clinical pancreatitis), CT findings (cyst size > 3 cm, the presence of enhancing mural nodules) and EUS features (the presence of mural nodules, the mural nodule size > 5 mm) were significant risk factors predicting malignant BD-IPMNs. Multivariate analysis revealed that the cyst size > 3 cm (odds ratio = 9.9), the presence of enhancing mural nodules on CT (odds ratio = 19.3) and the mural nodule size > 5 mm on EUS (odds ratio = 14.9) were the independent risk factors for the presence of malignancy in BD-IPMNs (p < 0.001).

CONCLUSIONS

The cyst size > 3 cm, the presence of enhancing mural nodules on CT, the mural nodule size > 5 mm on EUS are three independent predictors of malignancy in patients with 'pure' BD-IPMNs.

Does PET with CT Have Clinical Utility in the Management of Patients with Intraductal Papillary Mucinous Neoplasm?

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are well-established pancreatic precancerous lesions. Indications for resection are outlined in the 2012 International Consensus Guidelines (ICG). Because of the low specificity of the ICG, many patients will undergo potentially unnecessary surgery for nonmalignant IPMNs. Several retrospective studies have reported that positron emission tomography (PET) with CT (PET/CT) is highly sensitive and specific in detecting malignant IPMNs. We hypothesized that PET/CT complements the ICG in identification of malignant IPMNs.

STUDY DESIGN

From 2009 to 2013, patients with a suspected clinical or cytopathologic diagnosis of IPMN were prospectively enrolled in a clinical trial at a single center. Results of preoperative PET/CT on determination of IPMN malignancy (ie, high-grade dysplastic and invasive) was compared with surgical pathology. PET/CT uptake was considered increased if the standardized uptake value was ≥3.

RESULTS

Of the 67 patients enrolled, 50 patients met all inclusion criteria. Increased PET/CT uptake was associated with significantly more malignant and invasive IPMNs (80% vs 13%; p < 0.0001 and 40% vs 3%; p = 0.004). When patients were divided into branch duct and main duct IPMNs, increased PET/CT uptake was also associated with more malignancy (60% vs 0%; p = 0.006 for branch duct IPMN and 100% vs 23%; p = 0.003 for main duct IPMN). Patients with ICG criteria (eg, worrisome features and high-risk stigmata) and increased PET/CT uptake had more malignant and invasive IPMNs than patients with ICG criteria, but no increased uptake (78% vs 17%; p = 0.001 and 33% vs 3%; p = 0.03). The sensitivity and specificity of the ICG criteria for detecting malignancy were 92% and 27%, respectively, and PET/CT was less sensitive (62%) but more specific (95%). When PET/CT was added to ICG criteria, the association resulted in 78% sensitivity and 100% specificity.

CONCLUSIONS

The addition of PET/CT to preoperative workup improves the performance of the ICG for predicting malignant risk in patients with IPMN.

Surgery for cystic pancreatic lesions in the post-sendai era: a single institution experience

Introduction. The management of cystic pancreatic lesions has changed in recent years as a result of increasing knowledge of their biological behaviour, better diagnostic options, and international guidelines. Methods. Retrospective analysis of a cohort of 86 patients operated for cystic pancreatic lesions during a seven-year period (2007–2014). Results. Final histopathology revealed 53 intraductal papillary mucinous neoplasms (19 branch duct IPMNs, 15 mixed type IPMNs, and 19 main duct IPMNs), 14 serous and 13 mucinous cystic neoplasms, 3 solid pseudopapillary neoplasms, and 3 other lesions. 4 cases displayed high grade intraepithelial neoplasia and 2 cases displayed invasive cancer. A pylorus-preserving partial duodenopancreatectomy was carried out in 27 patients, a total pancreatectomy was carried out in 9 patients, a left resection was carried out in 42 patients, and segmental resections and enucleations were carried out in 4 patients each. Overall postoperative morbidity and mortality were 40% and 2.3%, respectively. The preoperative diagnosis of a specific cystic tumor was accurate in 79% of patients and 9 patients (10%) could have avoided surgery with the correct preoperative diagnosis. Conclusion. Cystic pancreatic lesions are still a diagnostic challenge, requiring a dedicated multidisciplinary approach. The rate of malignancy is relatively small, whereas postoperative morbidity is substantial, underscoring the importance of adequate patient selection considering both the risk of surgery and the long term risk of malignancy.

The natural history of main duct-involved, mixed-type intraductal papillary mucinous neoplasm: parameters predictive of progression

OBJECTIVE

As such, the natural history of MPD-involved IPMN is poorly understood.

BACKGROUND

The high-risk of malignancy associated with main pancreatic duct (MPD)-involved intraductal papillary mucinous neoplasm (IPMN) has been established by surgical series. The International Consensus Guidelines recommend surgical resection of MPD-involved IPMN in fit patients.

METHODS

A review of a prospectively collected database (1992-2012) of patients with IPMN undergoing primary surveillance was performed. Invasive progression was defined as invasive carcinoma on pathology and/or positive cytopathology. Analyses included univariate, logistic regression, and receiver operating characteristic curve analyses.

RESULTS

A total of 503 patients with IPMN underwent primary surveillance, 70 for MPD-involved, mixed-type IPMN. Indications for intensive surveillance of these 70 high-risk patients were comorbidities, patient choice, and early/borderline MPD dilation (42%, 51%, and 7%, respectively). Mean follow-up was 4.7 years. Nine patients (13%) progressed at a mean of 3.5 (range, 1-9) years during follow-up. Univariate analyses yielded weight loss, interval (from isolated branch-duct IPMN) to MPD involvement, diffuse MPD dilation, increase of MPD diameter, absence of extra pancreatic cysts, elevated serum CA19-9 levels, and elevated serum alkaline phosphatase levels as significant. Maximum MPD and/or branch-duct diameter were not significant. In logistic regression, diffuse MPD dilation, serum CA19-9 and serum alkaline phosphatase levels, and absence of extra pancreatic cysts were predictors of invasiveness. The receiver operating characteristic curve indicated that the combination of these 4 factors achieved an accuracy of 98% in predicting progression.

CONCLUSIONS

Primary surveillance of mixed-type IPMN may be a reasonable strategy in select patients. Diffuse MPD dilation, serum CA19-9, serum alkaline phosphatase, and absence of extrapancreatic cysts predict patients likely to progress during primary surveillance.

Intraductal papillary mucinous neoplasms of the pancreas: evaluation of malignant potential and surgical resectability by using MR imaging with MR cholangiography

PURPOSE

To evaluate the diagnostic performance of magnetic resonance (MR) imaging with MR cholangiopancreatography (MRCP) in determining the malignant potential and surgical resectability of pancreas intraductal papillary mucinous neoplasms (IPMNs).

MATERIALS AND METHODS

Institutional review board approval was obtained, and the requirement for informed consent was waived. Ninety-eight patients with pathologically proved pancreas IPMNs who underwent MR imaging with MRCP comprised the study population. MR images were analyzed for findings suggestive of high-risk stigmata or worrisome features, as proposed by the international consensus guidelines 2012. Interobserver agreement between two experienced observers (observers 1 and 2) and one inexperienced observer (observer 3) was assessed. Diagnostic performance of MR imaging in the evaluation of the malignant potential and surgical resectability of IPMNs was analyzed in these three observers by using receiver operating curve analysis.

RESULTS

MR imaging with MRCP showed sensitivity of 83% (35/42), 79% (33/42), and 90% (38/42); specificity of 80% (41/51), 51% (26/51), and 24% (12/51); and accuracy of 82% (76/93), 63% (59/93), and 54% (50/93) for observers 1, 2, and 3, respectively, in the evaluation of the malignant potential of pancreas IPMNs when at least one worrisome feature was present. Interobserver agreement in the detection of intramural nodules (κ = 0.349-0.574), enhanced solid components (κ = 0.318-0.574), and measurement of main pancreatic duct diameter (intraclass correlation coefficient = 0.9477) was fair to high. The respective sensitivity, specificity, and accuracy in determination of surgical resectability were 95% (81/85), 99% (84/85), and 88% (75/85); 69% (9/13), 69% (9/13), and 54% (7/13); and 92% (90/98), 95% (93/98), and 84% (82/98) for observers 1, 2, and 3.

CONCLUSION

MR imaging with MRCP is a useful modality in the evaluation of the malignant potential and resectability of IPMNs, with high sensitivity and moderate specificity in the experienced radiologists but relatively low specificity in the inexperienced radiology trainee.