Differential Diagnosis of Benign or Malignant Intraductal Papillary Mucinous Neoplasm of the Pancreas by Multidetector Row Helical Computed Tomography: Evaluation of Predictive Factors by Logistic Regression Analysis

Pancreatic intraductal papillary mucinous neoplasms: Current diagnosis and management

Intraductal papillary mucinous neoplasms (IPMNs) represent approximately 1% of all pancreatic neoplasms and 25% of cystic neoplasms. They are divided into three types: main duct-IPMN (MD-IPPMN), branch duct-IPMN (BD-IPMN), and mixed type-IPMN. In this review, diagnostics, including clinical presentation and radiological investigations, were described. Magnetic resonance imaging is the most useful for most IPMNs. Management depends on the type and radiological features of IPMNs. Surgery is recommended for MD-IPMN. For BD-IPMN, management involves surgery or surveillance depending on the tumor size, cyst growth rate, solid components, main duct dilatation, high-grade dysplasia in cytology, the presence of symptoms (jaundice, new-onset diabetes, pancreatitis), and CA 19.9 serum level. The patient’s age and comorbidities should also be taken into consideration. Currently, there are different guidelines regarding the diagnosis and management of IPMNs. In this review, the following guidelines were presented: Sendai International Association of Pancreatology guidelines (2006), American Gastroenterological Association guidelines, revised international consensus Fukuoka guidelines (2012), revised international consensus Fukuoka guidelines (2017), and European evidence-based guidelines according to the European Study Group on Cystic Tumours of the Pancreas (2018). The Verona Evidence-Based Meeting 2020 was also presented and discussed.

Imaging Features for Predicting High-Grade Dysplasia or Malignancy in Branch Duct Type Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Systematic Review and Meta-Analysis

BACKGROUND

The consensus guidelines for branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas are mostly based on imaging features. This study aimed to determine imaging features and their diagnostic accuracy for predicting high-grade dysplasia (HGD)/malignancy in BD-IPMN, including mixed type.

METHODS

The PubMed, Embase, and Cochrane databases were searched, and data were extracted from relevant studies. As the main diagnostic accuracy index, diagnostic odds ratios (DORs) of imaging features for diagnosing HGD/malignancy in BD-IPMNs were pooled using the random-effects model. A bivariate random-effects approach was used to construct summary receiver operating characteristic curves for sensitivity and specificity estimation.

RESULTS

The pooled DOR was the highest for the enhanced solid component/mural nodule (MN) (DOR, 12.21; 95 % confidence interval [CI], 6.14-24.27), followed by a main pancreatic duct (MPD) diameter of 10 mm or greater (DOR, 7.93; 95 % CI, 3.02-20.83), solid component (DOR, 4.85; 95 % CI, 2.49-9.42), lymphadenopathy (DOR, 4.84; 95 % CI, 1.11-21.06), MN (DOR, 4.48; 95 % CI, 3.15-6.39), an MPD diameter of 5 mm or greater (DOR, 3.69; 95 % CI, 2.62-5.19), abrupt change in MPD caliber with distal pancreatic atrophy (DOR, 2.65; 95 % CI, 1.66-4.24), thickened/enhancing walls (DOR, 2.38; 95 % CI, 1.57-3.60), and cyst size of 3 cm or larger (DOR, 1.98; 95 % CI, 1.48-2.64). The largest area under the curve (0.89 and 0.95, respectively) and high specificity (0.95 and 0.98, respectively) also were found for enhanced solid component/MN and an MPD diameter of 10 mm or greater, albeit with low sensitivity (0.38 and 0.14, respectively).

CONCLUSIONS

The aforementioned imaging features could aid in predicting HGD/malignancy of BD-IPMN. Furthermore, enhanced solid component/MN and an MPD diameter of 10 mm or greater were the most important predictors of HGD/malignancy in BD-IPMN and should be considered as indications for surgery.

Predictive Features of Malignancy in Branch Duct Type Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Meta-Analysis

Simple Summary

Currently, there are several guidelines that are widely used to establish the treatment strategy for branch duct type intraductal papillary mucinous neoplasms. Although there are some common grounds, there are discrepancies on which features they adopt, how much each feature is weighted, and how the features are combined. Furthermore, some of the features are based on lower level evidences or expert opinions. The aim of this meta-analysis was to investigate important clinical, radiological, and biochemical risk factors for malignancy and their impact as predictors. This study found symptom, size, cyst wall thickening, presence of mural nodule, change in main pancreatic duct caliber, lymphadenopathy, CA 19-9, and CEA as risk factors. Lymphadenopathy (odd ratio [OR]: 8.55), abrupt caliber change (OR: 7.41), and mural nodule (OR: 4.10) had the highest odd ratios. We expect the higher level evidences of this study to help shape better guidelines and reduce discrepancies among future guidelines.

Abstract

The current guidelines on branch duct type intraductal papillary mucinous neoplasm (BD-IPMN) recommend various predictive features of malignancy as well as different treatment strategies. This study aimed to identify the risk factors for malignancy with higher level of evidence. A meta-analysis was performed on 40 literatures published between 2000 and 2019. These literatures included 6301 patients with pathologically proven IPMN. Malignancy was defined as high-grade dysplasia and invasive carcinoma. It was significantly associated with symptoms (odds ratio [OR] 1.35, confidence interval [CI] 1.01–1.79), size ≥ 3 cm (OR 1.90, CI 1.51–2.40), cystic wall thickening (OR 2.53, CI 1.50–4.27), mural nodule (OR 4.10, CI 3.38–4.97), main pancreatic duct dilatation (OR 2.98, CI 2.11–4.21), abrupt caliber change of the pancreatic duct (OR 7.41, CI 2.49–22.06), lymphadenopathy (OR 8.55, CI 3.25–22.51), elevated carbohydrate antigen 19-9 (OR 4.01, CI 2.55–6.28), and elevated carcinoembryonic antigen (OR 2.04, CI 1.60–2.61). Multilocular cysts and multiple cysts did not show a significant association with malignancy. This study examined the clinical, radiological, and biochemical features of BD-IPMN, often used as malignancy predictors according to the widely used guidelines. The results confirmed that all the features currently being used are valid.

Predictive performance of factors associated with malignancy in intraductal papillary mucinous neoplasia of the pancreas

Background

Estimation of the risk of malignancy in intraductal papillary mucinous neoplasia (IPMN) of the pancreas is a clinical challenge. Several routinely used clinical factors form the basis of the current consensus guidelines. This study aimed to determine the predictive values of the most commonly assessed risk factors.

Methods

A meta-analysis of individual risk factors of malignancy in IPMN was performed. Contingency tables were derived from these data, and sensitivity, specificity, negative and positive predictive values, and diagnostic odds ratios (DOR) were determined. Hierarchical summary receiver operating characteristic (HSROC) curves for each factor were calculated and the respective area under the curve (AUC) was assessed.

Results

A total of 3443 studies were screened initially. Analysis of recent literature revealed 60 studies with 13 relevant risk factors including clinical, serological and radiological parameters. The largest area under the HSROC curve was found for weight loss (0·84) and jaundice/raised bilirubin level (0·80), followed by increased carcinoembryonic antigen (CEA) (0·79) or carbohydrate antigen (CA) 19-9 (0·78) levels. The most sensitive factors were patient age (71 per cent) and mural nodules (65 per cent), and jaundice/raised bilirubin level (97 per cent) and increased CEA level (95 per cent) were most specific. None of the analysed factors reached a positive or negative level of prediction beyond 90 per cent.

Conclusion

None of the established criteria safely distinguishes malignant from non-malignant lesions.

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.

What Is the Best Way to Identify Malignant Transformation Within Pancreatic IPMN: A Systematic Review and Meta-Analyses

OBJECTIVES

Pancreatic intraductal papillary mucinous neoplasias (IPMNs) represent 25% of all cystic neoplasms and are precursor lesions for pancreatic ductal adenocarcinoma. This study aims to identify the best imaging modality for detecting malignant transformation in IPMN, the sensitivity and specificity of risk features on imaging, and the usefulness of tumor markers in serum and cyst fluid to predict malignancy in IPMN.

METHODS

Databases were searched from November 2006 to March 2014. Pooled sensitivity and specificity of diagnostic techniques/imaging features of suspected malignancy in IPMN using a hierarchical summary receiver operator characteristic (HSROC) approach were performed.

RESULTS

A total of 467 eligible studies were identified, of which 51 studies met the inclusion criteria and 37 of these were incorporated into meta-analyses. The pooled sensitivity and specificity for risk features predictive of malignancy on computed tomography/magnetic resonance imaging were 0.809 and 0.762 respectively, and on positron emission tomography were 0.968 and 0.911. Mural nodule, cyst size, and main pancreatic duct dilation found on imaging had pooled sensitivity for prediction of malignancy of 0.690, 0.682, and 0.614, respectively, and specificity of 0.798, 0.574, and 0.687. Raised serum carbohydrate antigen 19-9 (CA19-9) levels yielded sensitivity of 0.380 and specificity of 0903. Combining parameters yielded a sensitivity of 0.743 and specificity of 0.906.

CONCLUSIONS

PET holds the most promise in identifying malignant transformation within an IPMN. Combining parameters increases sensitivity and specificity; the presence of mural nodule on imaging was the most sensitive whereas raised serum CA19-9 (>37 KU/l) was the most specific feature predictive of malignancy in IPMNs.

CT of the pancreas: comparison of image quality and pancreatic duct depiction among model-based iterative, adaptive statistical iterative, and filtered back projection reconstruction techniques

The purpose of this study is to compare CT images of the pancreas reconstructed with model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASiR), and filtered back projection (FBP) techniques for image quality and pancreatic duct (PD) depiction. Data from 40 patients with contrast-enhanced abdominal CT [CTDIvol: 10.3 ± 3.0 (mGy)] during the late arterial phase were reconstructed with FBP, 40% ASiR-FBP blending, and MBIR. Two radiologists assessed the depiction of the main PD, image noise, and overall image quality using 5-point scale independently. Objective CT value and noise were measured in the pancreatic parenchyma, and the contrast-to-noise ratio (CNR) of the PD was calculated. The Friedman test and post-hoc multiple comparisons with Bonferroni test following one-way ANOVA were used for qualitative and quantitative assessment, respectively. For the subjective assessment, scores for MBIR were significantly higher than those for FBP and 40% ASiR (all P < 0.001). No significant differences in CT values of the pancreatic parenchyma were noted among FBP, 40% ASiR, and MBIR images (P > 0.05). Objective image noise was significantly lower and CNR of the PD was higher with MBIR than with FBP and 40% ASiR (all P < 0.05). Our results suggest that pancreatic CT images reconstructed with MBIR have lower image noise, better image quality, and higher conspicuity and CNR of the PD compared with FBP and ASiR.

Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis

OBJECTIVE

To systematically determine the imaging findings for distinguishing malignant and benign branch-duct type intraductal papillary mucinous neoplasms (BD-IPMNs), including mixed type, and their diagnostic value through meta-analysis of published studies.

BACKGROUND

Management of BD-IPMNs, including mixed type, largely relies on imaging findings. The current knowledge on imaging findings to distinguish malignant and benign BD-IPMNs has weak evidence and is mostly from scattered individual retrospective studies.

METHODS

Thorough literature search in Ovid-MEDLINE and EMBASE databases was conducted to identify studies where findings of computed tomography, magnetic resonance imaging, and endoscopic ultrasonography of BD-IPMNs with or without main pancreatic duct (MPD) dilatation were correlated with surgical/pathological findings. Review of 1128 article candidates, including full-text review of 102 articles, identified 23 eligible articles with a total of 1373 patients for meta-analysis. Dichotomous data regarding distinction between malignant and benign BD-IPMNs were pooled using random effects model to obtain the diagnostic odds ratios (DORs) and their 95% confidence intervals (CIs) of various individual imaging findings for diagnosing malignant BD-IPMN.

RESULTS

Presence of mural nodules revealed the highest pooled DOR (95% CI) of 6.0 (4.1-8.8) followed by MPD dilatation [3.4 (2.3-5.2)], thick septum/wall [unadjusted, 3.3 (1.5-6.9); publication bias-adjusted, 2.3 (0.9-5.5)], and cyst size greater than 3 cm [2.3 (1.5-3.5)]. Multilocularity and multiplicity of the cystic lesions did not reveal statistically significant association with malignancy.

CONCLUSIONS

Presence of mural nodules should be regarded highly suspicious for malignancy warranting a surgical excision whereas cyst size greater than 3 cm, MPD dilatation (5-9 mm), or thick septum/wall may better be managed by careful observation and/or further evaluation.

Potential predictors of disease progression for main-duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND AND AIM

The evidence for main pancreatic duct intraductal papillary mucinous neoplasms (MPD-IPMN) malignancy is based predominantly on investigation of resected cases, and the natural history is still unclear. The aim of the present study is to investigate the natural history of MPD-IPMN and examine potential predictors of disease progression in MPD-IPMN patients who conformed to "high-risk stigmata" criteria.

METHODS

This study included consecutive 20 follow-up patients and 19 surgical patients with "high-risk stigmata" MPD-IPMN, in whom the diameter of the MPD was > 10 mm, branch duct was < 5 mm, and who underwent clinical follow up for ≥ 2 years.

RESULTS

Among surgical patients, mural nodules and MPD diameter of invasive patients were significantly different compared with non-invasive patients. On the other hand, among follow-up patients, univariate analysis revealed the following potential predictors for disease progression: diameter of MPD ≥ 15 mm (hazard ratio [HR], 20.9; 95% confidence interval [CI], 2.59-173.4; P < 0.01); and diffuse lesions of MPD-IPMN (HR, 4.46; 95% CI, 1.10-18.0; P = 0.04). On the other hand, multivariate analysis identified only diameter of MPD ≥ 15 mm (HR, 19.2; 95% CI, 1.87-198.5; P = 0.01) as a potential predictor of disease progression.

CONCLUSION

If MPD-IPMN patients have other severe complications or reasons for not undergoing surgical treatment, MPD diameter < 15 mm, negative cytology, and no mural nodules, conservative clinical follow up for several years may be an option.

Cyst features and risk of malignancy in intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis

BACKGROUND & AIMS

International guidelines for the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas recommend surgical resection of those with specific characteristics. We performed a meta-analysis to evaluate the risk of malignancy associated with each of these features of IPMNs.

METHODS

We performed a comprehensive search of MEDLINE from January 1, 1996, to November 11, 2011, for studies that included any of the features mentioned in the consensus guidelines for surgical resection of main duct and branch duct IPMNs. Data were analyzed from 41 studies for the following features: cyst size greater than 3 cm, the presence of mural nodules, dilated main pancreatic duct, symptoms, and main duct vs branch duct IPMNs. Malignant IPMNs were defined as those with carcinoma in situ or more advanced histology. A separate meta-analysis was performed for each risk factor to calculate pooled odds ratios (ORs). A random-effects model was used, based on the assumption of variation among study populations.

RESULTS

The risks of malignancy associated with individual cyst features were as follows: cyst size greater than 3 cm (OR, 62.4; 95% confidence interval [CI], 30.8-126.3), presence of a mural nodule (OR, 9.3; 95% CI, 5.3-16.1), dilatation of the main pancreatic duct (OR, 7.27; 95% CI, 3.0-17.4), and main vs branch duct IPMN (OR, 4.7; 95% CI, 3.3-6.9). There was a moderate level of heterogeneity among studies (I(2) range, 34-67).

CONCLUSIONS

Based on a meta-analysis, cyst features proposed by the international guidelines for resection of IPMN were highly associated with malignancy. However, based on our findings, not all cyst features should be weighted equally when considering risk of malignancy; cyst size greater than 3 cm was associated most strongly with malignant IPMN.

Cyst fluid SPINK1 may help to differentiate benign and potentially malignant cystic pancreatic lesions

OBJECTIVE

Differential diagnosis between benign and potentially malignant cystic pancreatic lesions may be difficult. Previously we have compared cyst fluid serine protease inhibitor Kazal type I (SPINK1) with some traditionally used tumour markers (amylase, CEA, Ca19-9) and found that it may be a new promising maker in the differential diagnosis of cystic pancreatic lesions. In the present study, we focused on cyst fluid SPINK1 levels in benign and potentially malignant cystic pancreatic lesions.

DESIGN

Sixty-one patients operated on for cystic pancreatic lesion in Tampere University Hospital, Finland and in Verona University Hospital, Italy, were included. Cyst fluid was aspirated during surgery, stored at -70 °C, and analysed with immunofluorometric assay for SPINK1. The final diagnosis was acute pancreatitis with fluid collection (Acute FC) in 4 patients, chronic pseudocyst (PS) in 17 patients, serous cystadenoma (SCA) in 7 patients, mucinous cystadenoma (MCA) in 21 patients and intraductal papillary-mucinous neoplasm (IPMN) in 12 patients (9 main/mixed duct type and 3 branch duct type).

RESULTS

The acute FC patients had high SPINK1 levels. Among chronic cysts, SPINK1 levels were significantly higher in patients with potentially malignant cysts (main/mixed duct IPMN and MCA) than with benign cysts (side branch IPMN and SCA), (median and range, [480 (13-3602) vs. 18 (0.1-278) μg/L]; p < 0.0001). In the subcohort of 24 patients with <3 cm chronic cyst, cyst fluid SPINK 1 levels were significantly lower in SCA or side branch IPMN (3 [2-116] μg/L) than in main duct IPMN or MCA (638 [66-3602] μg/L; p = 0.018). The best sensitivity and specificity to differentiate any size MCA or main/mixed type IPMN from SCA or side branch IPMN were 85% and 84% (AUC 0.94; cut-off value 118 μg/L). The best sensitivity and specificity to differentiate <3 cm MCA or main duct IPMN from SCA or side branch IPMN were 93% and 89% (AUC 0.98; cut-off value 146 μg/L).

CONCLUSIONS

Cyst fluid SPINK1 may be a possible marker in the differential diagnosis of benign and potentially malignant cystic pancreatic lesions.

Added value of diffusion-weighted imaging to MR cholangiopancreatography with unenhanced mr imaging for predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm of the pancreas

PURPOSE

To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) with unenhanced MR imaging for predicting the malignancy or invasiveness of intraductal papillary mucinous neoplasms (IPMNs).

MATERIALS AND METHODS

Following Institutional Review Board (IRB) approval, this retrospective study included 52 patients with surgically resected IPMNs and who underwent MRCP, unenhanced MRI, and DWI. Three blinded radiologists evaluated the two image sets, ie, MRCP with unenhanced MR images vs. the combined set with MRCP, unenhanced MR images, and DWI, and scored their confidence for malignancy or for invasiveness of IPMNs. The mean apparent diffusion coefficient (ADC) values of benign IPMNs and of intraductal mucinous carcinomas (IPMCs) were compared. The diagnostic accuracy was calculated using receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean ADC of malignant IPMNs (2.05 ± 0.66 × 10(-3) mm(2) /sec) was significantly lower than that of benign IPMNs (2.95 ± 0.32 × 10(-3) mm(2) /sec, P < 0.0001). Invasive IPMCs (1.51 ± 0.32 × 10(-3) mm(2) /sec) showed significantly lower ADC than that of noninvasive IPMCs (2.67 ± 0.23 × 10(-3) mm(2) /sec, P = 0.0003). The area of diffusion restriction was more frequently seen in malignant IPMNs than in benign IPMNs (P < 0.00001). The addition of DWI to MRCP with unenhanced MRI did not show a significant improvement for predicting malignant IPMN (P> 0.05), but resulted in a tendency to improve the diagnostic accuracy for the prediction of invasive IPMN in two observers (P = 0.072, P = 0.085).

CONCLUSION

The addition of DWI to MRCP with unenhanced MRI may improve the diagnosis of malignant IPMN and further increase the prediction of invasive IPMC.

Comparison of MRI and endoscopic ultrasound in the characterization of pancreatic cystic lesions

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of MRI and endoscopic ultrasound (EUS) for the characterization of cystic pancreatic lesions and prediction of malignancy.

MATERIALS AND METHODS

Fifty patients (24 women and 26 men; average age, 57 years) underwent both MRI and EUS. All pancreatic lesions (21 cystic and 29 solid lesions) were proven by histopathologic analysis. Two radiologists retrospectively examined MR images, and a single gastroenterologist reviewed EUS images. The MRI and EUS characterizations of morphologic features of the cystic lesions and predictions of malignancy were evaluated. The prediction of malignancy was done by receiver operating characteristic (ROC) curve analysis.

RESULTS

There was no difference between the ability of MRI and EUS to correctly classify lesions as cystic or solid (accuracy, 90-98% vs 88%; p > 0.05). There was no difference between the sensitivity of MRI and EUS for the characterization of septa (94.4% for MRI vs 77.8% for EUS), mural nodule (66.7-58.3% for MRI vs 58.3% for EUS), main pancreatic duct dilatation (92.9-85.7% for MRI vs 85.7% for EUS), and communication with main pancreatic duct (100% for MRI vs 88.9% for EUS). The area under ROC curve values for predicting malignancy showed no statistical significance (0.755-0.774 for MRI vs 0.769 for EUS; p > 0.894).

CONCLUSION

MRI and EUS are comparable in the characterization of cystic pancreatic lesions and prediction of malignancy.

Acute pancreatitis in patients operated on for intraductal papillary mucinous neoplasms of the pancreas: frequency, severity, and clinicopathologic correlations

OBJECTIVES

Acute pancreatitis (AP) may reveal intraductal papillary mucinous neoplasms of the pancreas (IPMN). The aims were to describe the characteristics of AP associated with IPMN and to compare patients with AP with those without AP.

METHODS

All patients who underwent surgery for IPMN between 1995 and 2006 were retrospectively studied. Clinical, imaging, and histological data were collected. The clinical and radiological severity of AP, the number of episodes, and recurrence after surgery were assessed.

RESULTS

One hundred eighty-five patients were included. Sixty-four (34.6%) had at least 1 AP (median, 2; range, 1-10). The median Balthazar score was 1 (0-6). Imaging analysis showed no difference between the 2 groups except for the presence of a mass. Branch duct IPMNs were more frequent in the AP group (74.4% vs 45.3%, P = 0.001), whereas combined IPMNs were more frequent in the non-AP group (45.3% vs 21.5%, P = 0.001). There was no difference in the grade of dysplasia between AP and non-AP groups: carcinoma, 45.3% versus 56.2%; benign IPMN, 54.7% versus 43.8% (P = NS), respectively.

CONCLUSIONS

Acute pancreatitis occurs in 34.6% of patients with IPMNs. Acute pancreatitis is not severe and often recurs. Histology showed no difference between the 2 groups.

Intraoperative ultrasound of the pancreas

Intraoperative ultrasound provides spatial resolution of the pancreas superior to computed tomography, magnetic resonance imaging, and transabdominal sonography. This pictorial essay will review common benign and malignant pancreatic processes including the following: pancreatic ductal adenocarcinoma, pancreatitis, endocrine tumors, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, serous cystadenoma, and solid pseudopapillary tumor. The use of intraoperative ultrasound in specific surgical situations will be discussed, which include the following: (1) identification of insulinoma(s) which are not detectable preoperatively, (2) identification of the pancreatic duct to determine dissection planes for chronic pancreatitis surgery (eg, Puestow procedure) and for tumor resection, and (3) staging purposes for malignant disease.