Main pancreatic duct dilation greater than 6 mm is associated with an increased risk of high-grade dysplasia and cancer in IPMN patients

Different Etiologies of Dilated Pancreatic Duct Based on Endoscopic Ultrasonography Findings

Background

Pancreatic duct (PD) dilation could be presented in both benign and malignant diseases. Endoscopic ultrasonography (EUS) is a sensitive modality that provides both structural assessment and tissue sampling. This study aims to explore the importance of PD dilation as a potential indicator related to various pancreatobiliary pathologies identified via EUS.

Methods

Among 3109 subjects who underwent EUS, 599 had evidence of dilated PD and met the inclusion criteria of this retrospective study. Also, the patients underwent EUS fine needle aspiration (EUS-FNA) to evaluate the etiology when required. All data were extracted from patients' medical records to perform statistical analysis.

Results

The study sample revealed 64% being male with a median age was 65-years. Pancreatic adenocarcinoma was the most common etiology diagnosed in 236 patients (39.4%), followed by sphincter of Oddi dysfunction (SOD) in 13% of subjects. Ampullary carcinoma, common bile duct stone, and cholangiocarcinoma were found at 9.5%, 8.8%, and 6.8%, respectively. Abdominal pain was the most common symptom seen in 440 (73.4%) patients. Opium consumption was reported in 170 (28.4%) subjects. Opium consumption was significantly more prevalent in patients with SOD (P<0.05).

Conclusion

We suggest that PD dilation could be associated with a wide range of pancreaticobiliary pathologies, especially pancreatic neoplasms. In this regard, PD dilation should be considered as a crucial indicator of pancreatic neoplasm despite it may be associated with no clear etiologies.

Association of high-risk stigmata and worrisome features with advanced neoplasia in intraductal papillary mucinous neoplasms (IPMN): A systematic review

BACKGROUND

This systematic review aimed to assess the diagnostic accuracy of the International Consensus Fukuoka Guidelines (ICG2017) in identifying high-risk lesions of Intraductal Papillary Mucinous Neoplasms (IPMNs).

METHODS

The ICG2017 revision committee conducted a comprehensive literature review to establish evidence-based statements on IPMNs. The review focused on articles examining the diagnostic value of imaging features (e.g., cyst or main pancreatic duct diameter), clinical symptoms associated with IPMN, and serum biomarkers. Five clinical questions regarding high-risk stigmata (HRS) and worrisome features (WF) in the ICG2017 guidelines were addressed.

RESULTS

A total of 210 articles were reviewed. The findings revealed a significant association between the presence of mural nodules ≥5 mm in diameter or solid components with contrast enhancement and the diagnosis of high-grade dysplasia or invasive carcinoma. Contrast-enhanced diagnostic tools, such as CT, MRI, or EUS, demonstrated the highest prediction rate and were recommended. Positive cytology was identified as an HRS, while symptoms like acute pancreatitis and cyst diameter growth ≥2.5 mm per year were considered WFs. The use of nomograms and multiple diagnostic factors was recommended for optimal IPMN management.

CONCLUSIONS

This systematic review provides evidence supporting the improved diagnostic accuracy of ICG2017 in identifying high-risk lesions of IPMN. The multidisciplinary incorporation of HRS and WF based on imaging findings and clinical symptoms is crucial. These findings should inform the revision of ICG2017, enhancing the evaluation and management of IPMN patients. By implementing these recommendations, clinicians can make more informed decisions, leading to better diagnosis and treatment outcomes for high-risk IPMN cases.

Intraoperative pancreatoscopy can improve the detection of skip lesions during surgery for intraductal papillary mucinous neoplasia: A pilot study

OBJECTIVES

Intraoperative pancreatoscopy is a promising procedure that might guide surgical resection for suspected main duct (MD) and mixed type (MT) intraductal papillary mucinous neoplasms (IPMNs). The aim of the present study was to assess the diagnostic yield and clinical impact of intraoperative pancreatoscopy in patients operated on for MD and MT-IPMNs.

METHODS

This is a retrospective cohort study. Patients undergoing surgery for suspected MD or MT-IPMN underwent intraoperative pancreatoscopy and frozen section analysis. In all patients who required extended resection due to pancreatoscopic findings, we compared the final histology with the results of the intraoperative frozen section analysis.

RESULTS

In total, 46 patients, 48% females, mean age (range) 67 years (45-82 years) underwent intraoperative pancreatoscopy. No mortality or procedure related complications were observed. Pancreatoscopy changed the operative course in 30 patients (65%), leading to extended resections in 20 patients (43%) and to parenchyma sparing procedures in 10 patients (22%). Analyzing the group of patients who underwent extended resections, 7 (35%) displayed lesions that needed further surgical treatment (six high grade dysplasia and one with G1 pancreatic neuroendocrine tumor) and among those 7, just 1 (14%) would have been detected exclusively with histological frozen section analysis of the transection margin. The combination of both pancreatoscopy and frozen section analysis lead to 86% sensitivity and 92% specificity for the detection of pathological tissue in the remnant pancreas.

CONCLUSION

Intraoperative pancreatoscopy is a safe and feasible procedure and might allow the detection of skip lesions during surgery for suspect MD-involving IPMNs.

Pre-emptive resection for intraductal papillary mucinous neoplasia - Long-term outcome is similar between non-invasive and early invasive lesions in a tertiary single center

BACKGROUND

Pre-emptive resection for intraductal papillary mucinous neoplasm (IPMN) aims to reduce the risk before invasive transformation has taken place. Pancreatic resections are highly associated with major morbidity and mortality. Long-term overall survival (OS) after resection for invasive IPMN (inv-IPMN) in early stages is favorable. Comparison of long-term OS for resected non-invasive IPMN and early staged inv-IPMN is poorly delineated. This study aims to compare outcomes for resected non-invasive IPMN and T1-staged inv-IPMN.

METHODS

All patients ≥18 years of age resected for IPMN up to stage T1 at Karolinska University Hospital between 2008 and 2020 were included. Two-year OS were compared between groups by chi-squared test, and 5-year OS was estimated using Kaplan-Meier method. Covariates associated with death was assessed in multivariable Cox regression model.

RESULTS

We included 284 patients, 264 (93%) non-invasive IPMN and 20 (7%) T1-staged inv-IPMN. Dysplasia of low grade (LGD) and high grade, i.e., tumor in situ (Tis) were present in 190 (67%) and 75 (26%) patients respectively. The 2-year OS for the entire cohort was 96%, and there were no differences between non-invasive and inv-IPMN (96% vs 92%, p = 0.203), nor between IPMN with LGD and Tis-T1b-staged IPMN (96% vs 95%, p = 0.734).

CONCLUSION

Two thirds of the specimen from pre-emptive resections were of LGD and did not involve superior OS than in situ or early cancer. Due to high complication burden, efforts should be made to avoid resection when LGD is probable and rather identify more accurate predictors for surgery.

Patients with deleterious germline mutations: A heterogeneous population for pancreatic cancer screening?

BACKGROUND AND OBJECTIVES

Modest data exist on the benefits of screening and surveillance for pancreatic cancer (PC) in high-risk individuals. Intraductal papillary mucinous neoplasms (IPMN) are known precursors to PC. We hypothesized that patients with high-risk deleterious germline mutations have a higher prevalence of IPMN.

METHODS

All patients undergoing prospective screening at a single institution from 2013 to 2019 were reviewed.

RESULTS

Of 1166 patients screened, 358 (31%) possessed germline mutations and/or family history of PC (mutations n = 201/358, 56%, family history n = 226/358, 63%) (median follow-up 2.7 years). IPMN was found in 127 patients (35.5%). The prevalence of IPMN in mutation carriers (18%) was higher than in the general population (p < 0.01). Germline mutation was an independent predictor of IPMN (odds ratio [OR] = 3.2; p < 0.01), while family history was not (p = 0.22). IPMN prevalence was distributed unevenly between mutation types (67%-Peutz-Jeghers; 43%-HNPCC, 24%-BRCA2; 17%-ATM; 9%-BRCA1; 0%-CDKN2A and PALB2).

CONCLUSION

In this series, 18% of mutation carriers harbored IPMN, higher than the general population. Germline mutation, but not a family history of PC, was independently associated with IPMN. This prevalence varied across mutation subtypes, suggesting not all mutation carriers develop precancerous lesions. Genetic testing for patients with a positive family history may improve screening modalities for this high-risk population.

Long-term (10-year) outcomes and prognostic factors in resected intraductal papillary mucinous neoplasm tumors in Finland: A nationwide retrospective study

BACKGROUND

The degree of dysplasia is the most important prognostic factor for patients with resected intraductal papillary mucinous neoplasms. Intraductal papillary mucinous neoplasms are predominantly premalignant conditions; in most cases, surveillance is an adequate treatment. If worrisome features are present, surgery should be considered. However, there is limited data on the long-term prognosis of resected intraductal papillary mucinous neoplasms. We aimed to ascertain the nationwide survival of patients with resected intraductal papillary mucinous neoplasms and identify factors associated with survival.

METHODS

This is a retrospective nationwide cohort study. All intraductal papillary mucinous neoplasms operated on in Finland between 2000 and 2008 were identified. Patient records were evaluated, and original radiologic data and histologic samples were re-evaluated. Survival data were collected after a 10-year follow-up period.

RESULTS

Out of 2,024 pancreatic resections, 88 were performed for intraductal papillary mucinous neoplasm. The median age of the patients was 65 years. Histologic diagnoses were main duct intraductal papillary mucinous neoplasm 47/88 (53,4%), mixed-type intraductal papillary mucinous neoplasm 27/88 (30.7%), and branchduct intraductal papillary mucinous neoplasm 14/88 (15.9%). Of the tumors, 40/88 (45.5%) were low-grade dysplasia, 9/88 (10.2%) high-grade, and 39/88 (44.3%) were invasive cancer. The median survival was 121 (range 0-252) months. Ten-year survival was 72.5%, 66.7%, and 23.1% in the low-grade dysplasia, high-grade dysplasia, invasive cancer groups, respectively. Ten-year mortality for pancreatic cancer was 5%, 9.1%, and 71.8% in the low-grade dysplasia, high-grade dysplasia, invasive cancer groups, respectively.

CONCLUSION

Overall, 44.3% of the patients had a malignant tumor, and three-quarters (74.5%) of the main duct intraductal papillary mucinous neoplasms were malignant or high-grade dysplasia at the time of surgery. Ten-year survival was significantly better in patients operated on at the stage of a premalignant tumor (low-grade dysplasia + high-grade dysplasia) than in patients operated on at the stage of a malignant tumor.

The effectiveness of endoscopic ultrasonography findings to distinguish benign and malignant intraductal papillary mucinous neoplasm

BACKGROUND AND AIMS

Accurate evaluation of intraductal papillary mucinous neoplasm (IPMN) is necessary to inform clinical decision-making. But it is still difficult to distinguish benign and malignant IPMN preoperatively. This study aims to evaluate the utility of EUS to predict the pathology of IPMN.

METHODS

Patients with IPMN who underwent endoscopic ultrasound within 3 months before surgery were collected from six centers. Logistic regression model and random forest model were used to determine risk factors associated with malignant IPMN. In both models, 70% and 30% of patients were randomly assigned to the exploratory group and validation group, respectively. Sensitivity, specificity, and ROC were used in model assessment.

RESULTS

Of the 115 patients, 56 (48.7%) had low-grade dysplasia (LGD), 25 (21.7%) had high-grade dysplasia (HGD), and 34 (29.6%) had invasive cancer (IC). Smoking history (OR = 6.95, 95%CI: 1.98-24.44, p = 0.002), lymphadenopathy (OR = 7.91, 95%CI: 1.60-39.07, p = 0.011), MPD > 7 mm (OR = 4.75, 95%CI: 1.56-14.47, p = 0.006) and mural nodules > 5 mm (OR = 8.79, 95%CI: 2.40-32.24, p = 0.001) were independent risk factors predicting malignant IPMN according to the logistic regression model. The sensitivity, specificity, and AUC were 0.895, 0.571, and 0.795 in the validation group. In the random forest model, the sensitivity, specificity, and AUC were 0.722, 0.823, and 0.773, respectively. In patients with mural nodules, random forest model could reach a sensitivity of 0.905 and a specificity of 0.900.

CONCLUSIONS

Using random forest model based on EUS data is effective to differentiate benign and malignant IPMN in this cohort, especially in patients with mural nodules.

Salivary Polyamines Help Detect High-Risk Patients with Pancreatic Cancer: A Prospective Validation Study

Pancreatic cancer is one of the most malignant cancer types and has a poor prognosis. It is often diagnosed at an advanced stage because of the absence of typical symptoms. Therefore, it is necessary to establish a screening method for the early detection of pancreatic cancer in high-risk individuals. This is a prospective validation study conducted in a cohort of 1033 Japanese individuals (male, n = 467, age = 63.3 ± 11.5 years; female, n = 566, age = 64.2 ± 10.6 years) to evaluate the use of salivary polyamines for screening pancreatic diseases and cancers. Patients with pancreatic cancer were not included; however, other pancreatic diseases were treated as positive cases for accuracy verification. Of the 135 individuals with elevated salivary polyamine markers, 66 had pancreatic diseases, such as chronic pancreatitis and pancreatic cysts, and 1 had gallbladder cancer. These results suggest that the salivary polyamine panel is a useful noninvasive pancreatic disease screening tool.

Threshold of main pancreatic duct for malignancy in intraductal papillary mucinous neoplasm at head-neck and body-tail

Background

Main pancreatic duct (MPD) dilation is a high-risk stigmata/worrisome feature of malignancy in intraductal papillary mucinous neoplasms (IPMNs). The threshold of MPD diameter in predicting malignancy may be related to the lesion location. This study aimed to separately identify the thresholds of MPD for malignancy of IPMNs separately for the head-neck and body-tail.

Materials and methods

A total of 185 patients with pathologically confirmed IPMNs were included. Patient demographic information, clinical data, and pathological features were obtained from the medical records. Those IPMNs with high-grade dysplasia or with associated invasive carcinoma were considered as malignant tumor. Radiological data including lesion location, tumor size, diameter of the MPD, mural nodule, and IPMN types (main duct, MD; branch duct, BD; and mixed type, MT), were collected on computed tomography or magnetic resonance imaging. Serum carbohydrate antigen 19-9 levels, serum carcinoembryonic antigen levels, and the medical history of diabetes mellitus, chronic cholecystitis, and pancreatitis were also collected.

Results

Malignant IPMNs were detected in 31.6% of 117 patients with lesions in the pancreatic head-neck and 20.9% of 67 patients with lesions in the pancreatic body-tail. In MPD-involved IPMNs, malignancy was observed in 54.1% of patients with lesions in the pancreatic head-neck and 30.8% of patients with lesions in the pancreatic body-tail (p < 0.05). The cutoff value of MPD diameter for malignancy was 6.5 mm for lesions in the head-neck and 7.7 mm for lesions in the body-tail in all type of IPMNs. In MPD-involved IPMNs, the threshold was 8.2 mm for lesion in pancreatic head-neck and 7.7 mm for lesions in the body-tail. Multivariate analysis confirmed that MPD diameter ≥ 6.5 mm (pancreatic head-neck) and MPD diameter ≥ 7.7 mm (pancreatic body-tail) were independent predictors of malignancy (p < 0.05). Similar results were observed in MPD-involved IPMNs using 8.2 mm as a threshold.

Conclusion

The thresholds of the dilated MPD may be associated with IPMNs locations. Thresholds of 6.5 mm for lesions in the head-neck and 7.7 mm for lesions in the body-tail were observed. For MPD-involved IPMNs alone, threshold for lesions in the head-neck was close to that in the body-tail.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02577-3.

Branch-duct intraductal papillary mucinous neoplasm (IPMN): Are cyst volumetry and other novel imaging features able to improve malignancy prediction compared to well-established resection criteria?

OBJECTIVES

Current guidelines base the management of intraductal papillary mucinous neoplasms (IPMN) on several well-established resection criteria (RC), including cyst size. However, malignancy may occur in small cysts. Since branch-duct (BD) IPMN are not perfect spheres, volumetric and morphologic analysis might better correlate with mucin production and grade of dysplasia. Nonetheless, their role in malignancy (high-grade dysplasia/invasive cancer) prediction has been poorly investigated. Previous studies evaluating RC also included patients with solid-mass-forming pancreatic cancer (PC), which may affect the RC yield. This study aimed to assess the role of volume, morphology, and other well-established RC in malignancy prediction in patients with BD- and mixed-type IPMN after excluding solid masses.

METHODS

Retrospective ethical review-board-approved study of 106 patients (2008-2019) with histopathological diagnosis of BD- and mixed-type IPMN (without solid masses) and preoperative MRI available. Standard imaging and clinical features were collected, and the novel imaging features cyst-volume and elongation value [EV = 1 - (width/length)] calculated on T2-weighted images. Logistic regression analysis was performed. Statistical significance set at two-tails, p < 0.05.

RESULTS

Neither volume (odds ratio (OR) = 1.01, 95% CI: 0.99-1.02, p = 0.12) nor EV (OR = 0.38, 95% CI: 0.02-5.93, p = 0.49) was associated with malignancy. Contrast-enhancing mural nodules (MN), main pancreatic duct (MPD) ≥ 5 mm, and elevated carbohydrate antigen (CA) 19-9 serum levels (> 37 μmol/L) were associated with malignancy (MN OR: 4.32, 95% CI: 1.18-15.76, p = 0.02; MPD ≥ 5 mm OR: 4.2, 95% CI: 1.34-13.1, p = 0.01; CA19-9 OR: 6.72; 95% CI: 1.89 - 23.89, p = 0.003).

CONCLUSIONS

Volume and elongation value cannot predict malignancy in BD- and/or mixed-type IPMN. Mural nodules, MPD ≥ 5 mm and elevated CA19-9 serum levels are associated with higher malignancy risk even after the exclusion of solid masses.

KEY POINTS

• Novel and well-established resection criteria for IPMN have been evaluated after excluding solid masses. • BD-IPMN volume and elongation value cannot predict malignancy. • Main pancreatic duct ≥ 5 mm, mural nodules, and elevated carbohydrate antigen 19-9 levels are associated with malignancy.

Pancreatic incidentalomas: Investigation and management

The incidence of pancreatic incidentalomas (PIs) detected in otherwise asymptomatic patients is growing with the increasing quality and use of advanced imaging techniques. PI can present as isolated main pancreatic duct dilation or as a solid or cystic lesion. Although historically thought to be relatively rare, PIs are rather common, particularly cystic lesions of the pancreas, which can be detected in up to 49% of the general population. With the poor prognosis of pancreatic cancer, PIs are an opportunity for prevention and early diagnosis, but when managed poorly, they can also lead to overtreatment and unnecessary morbidity. The management of PI should begin with a dedicated pancreas protocol computed tomography (CT) scan or magnetic resonance imaging (MRI) to accurately characterize duct size, lesion characteristics and establish an accurate baseline for subsequent follow up. Diagnosis and subsequent management depends on the extent of main duct dilation and solid versus cystic appearance. Solid lesions are highly concerning for malignancy. Cystic lesions can be further categorized as intraductal papillary mucinous neoplasms of the pancreas (IPMNs) or mucinous cystic neoplasms (MCNs), both of which harbour malignant potential, or as serous cystic neoplasms (SCNs) that are benign. In this paper, we summarize the major challenges related to PI and present pragmatic suggestions for management.

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.

The European evidence-based guidelines on pancreatic cystic neoplasms (PCN) in clinical practice: The development of relative and absolute indications for surgery during prospective IPMN surveillance

INTRODUCTION

The European evidence-based guidelines on PCN recommend surveillance for IPMN patients who are fit for surgery but who have no indication for immediate surgery. Our aim was to demonstrate the feasibility of the new guidelines in clinical practice.

METHODS

This is a prospective cohort study of patients included in the IPMN register in Tampere University Hospital, Finland. IPMN was diagnosed from January 1, 2013 to December 31, 2018. Patients were analyzed for surveillance and indications for surgery according to the European guidelines on PCN.

RESULTS

Out of 128 patients in register 23 was decided to operate upfront and 105 patients were included in the surveillance programme. Invasive carcinoma was found in 4/23 of operated patients. Median follow-up time was 26 months (6-69). Median size of the cyst at the beginning and end of the surveillance was 16 mm (4-58 mm). During surveillance 0/105 (0.0%) patients had or developed an absolute indication for surgery. Relative indication for surgery was present in 8/105 (7.6%) patients in the beginning surveillance and 9/105 (8.6%) patients developed at least one relative indication for surgery during surveillance. From the surveillance cohort 2/105 patients were operated. Surveillance was abandoned in 15/105 (14.1%) patients all due to poor general condition or other medical conditions.

CONCLUSIONS

In clinical practice, surveillance of IPMN according to the European guidelines on PCN is feasible. Among our patients 16% were detected to have relative indications for surgery during the median 26 (range 3-135) months of surveillance. Nearly 15% became surgically unfit during surveillance period.

Tumour markers and their utility in imaging of abdominal and pelvic malignancies

The utility of tumour biomarkers has increased considerably in the era of personalised medicine and individualised therapy in oncology. Biomarkers may be prognostic or predictive, and only a handful of markers are currently US Food and Drug Administration (FDA)-approved for clinical use. Tumour markers have a wide array of uses such as screening, establishing a differential diagnosis, assessing risk, prognosis, and treatment response, as well as monitoring disease status. Major overlap exists between biomarkers and their associated pathologies; therefore, despite suggestive imaging features, establishing a differential diagnosis may be challenging for the radiologist. We review common biomarkers that are of interest to radiologists such as carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH), prostate-specific antigen (PSA), beta human chorionic gonadotropin (β-hCG), carbohydrate antigen 19-9 (CA 19-9), alpha fetoprotein (AFP), and carbohydrate or cancer antigen 125 (CA 125), as well as their associated malignant and non-malignant pathologies. We also present relevant case examples from our practice.

Management of Incidental Pancreatic Cystic Lesions: Integrating Novel Diagnostic and Prognostic Factors With Current Clinical Guidelines

Owing to increased detection rates, the diagnosis and management of incidental pancreatic cysts has become a common predicament. Up to 13% of patients undergoing cross-sectional imaging studies for other indications are found to have pancreatic cystic lesions. Although most cystic lesions are benign, the malignant potential of several types of pancreatic cysts makes accurate classification vital to directing therapy. To this end, advances in the last decade led to better characterization of pancreatic cyst morphology and hence enhanced the ability to predict underlying histopathology, and biological behavior. Although accurate classification remains a challenge, the utilization of complementary diagnostic tools is the optimal approach to dictate management. The following review includes a description of pancreatic cysts, a critical review of current and emerging diagnostic techniques and a review of recent guidelines in the management of incidental pancreatic cysts.