Mural nodule of 10 mm or larger as predictor of malignancy for intraductal papillary mucinous neoplasm of the pancreas: Pathological and radiological evaluations

Enhancing Mural Nodules in the Main Pancreatic Duct of Main and Mixed Types of Intraductal Papillary Mucinous Neoplasms: Does Size Matter in Malignancy Risk?

Background/Aims

Most guidelines recommend surgical resection of all main duct (MD) and mixed-type (MT) intraductal papillary mucinous neoplasms (IPMNs) in suitable patients. However, there is little evidence regarding the malignancy risk of enhancing mural nodules (EMNs) that are present only in the main pancreatic duct (MPD) in patients with MD- and MT-IPMNs. Therefore, this study aimed to identify the clinical and morphological features associated with malignancy in MD- and MT-IPMNs with EMNs only in the MPD.

Methods

We retrospectively enrolled 50 patients with MD- and MT-IPMNs with EMNs only in the MPD on contrast-enhanced magnetic resonance imaging. We evaluated the clinical characteristics and preoperative radiologic imaging results of MPD morphology and EMN size and analyzed the risk factors associated with malignancy.

Results

Histological findings of EMNs were low-grade dysplasia (38%), malignant lesions (62%), high-grade dysplasia (34%), and invasive carcinoma (28%). On the receiver operating characteristic curve, the cutoff value of EMN size on magnetic resonance imaging for best predicting malignancy was 5 mm (sensitivity, 93.5%; specificity, 52.6%; area under the curve, 0.753). Multivariate analysis showed that only EMN >5 mm (odds ratio, 27.69; confidence interval, 2.75 to 278.73; p=0.050) was an independent risk factor for malignancy.

Conclusions

EMNs of >5 mm are associated with malignancy in patients with MD- and MT-IPMNs with EMNs that are present only in the MPD, in accordance with the international consensus guidelines.

A comparative study between computed tomography and endoscopic ultrasound in the detection of a mural nodule in intraductal papillary mucinous neoplasm -Multicenter observational study in Japan

BACKGROUND/OBJECTIVES

The detection of malignancy is a major concern in the management of intraductal papillary mucinous neoplasm (IPMN). The height of the mural nodule (MN), estimated using endoscopic ultrasound (EUS) and computed tomography (CT), has been considered crucial for predicting malignant IPMN. Currently, whether surveillance using CT or EUS alone is sufficient for detecting MNs remains unclear. This study aimed to compare the ability of CT and EUS to detect MNs in IPMN.

METHODS

This multicenter, retrospective observational study was conducted in 11 Japanese tertiary institutions. Patients who underwent surgical resection of IPMN with MN after CT and EUS examinations were eligible to participate. The MN detection rates between CT and EUS were examined.

RESULTS

Two-hundred-and-forty patients who underwent preoperative EUS and CT had pathologically confirmed MNs. The MN detection rates of EUS and CT were 83% and 53%, respectively (p < 0.001). Additionally, the MN detection rate of EUS was significantly higher than that of CT regardless of morphological type (76% vs. 47% in branch-duct-type IPMN; 90% vs. 54% in mixed IPMN; 98% vs. 56% in main-duct-type IPMN; p < 0.001). Further, pathologically confirmed MNs ≥5 mm were more frequently observed on EUS than on CT (95% vs. 76%, p < 0.001).

CONCLUSIONS

EUS was superior to CT for the detection of MN in IPMN. EUS surveillance is essential for the detection of MNs.

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.

Static and Dynamic 68Ga-FAPI PET/CT for the Detection of Malignant Transformation of Intraductal Papillary Mucinous Neoplasia of the Pancreas

Pancreatic ductal adenocarcinoma (PDAC) may arise from intraductal papillary mucinous neoplasms (IPMN) with malignant transformation, but a significant portion of IPMN remains to show benign behavior. Therefore, it is important to differentiate between benign IPMN and IPMN lesions undergoing malignant transformation. However, nonoperative differentiation by ultrasound, CT, MRI, and carbohydrate antigen 19-9 (CA19-9) is still unsatisfactory. Here, we assessed the clinical feasibility of additional assessment of malignancy by PET using ⁶⁸Ga-labeled fibroblast activation protein inhibitors (⁶⁸Ga-FAPI PET) in 25 patients with MRI- or CT-proven cystic pancreatic lesions. Methods: Twenty-five patients with cystic pancreatic lesions who were followed up in the European Pancreas Center of Heidelberg University hospital and who were led to surgical resection or fine-needle aspiration due to suspicious clinical, laboratory chemistry, or radiologic findings were examined by static (all patients) and dynamic (20 patients) ⁶⁸Ga-FAPI PET. Cystic pancreatic lesions were delineated and SUV_max and SUV_mean were determined. Time-activity curves and dynamic parameters (time to peak, K ₁, k ₂, K3, k ₄) were extracted from dynamic PET data. Receiver-operating curves of static and dynamic PET parameters were calculated. Results: Eleven of the patients had menacing IPMN (high-grade IPMN with [6 cases] or without [5 cases] progression into PDAC) and 11 low-grade IPMN; 3 patients had other benign entities. Menacing IMPN showed significantly elevated ⁶⁸Ga-FAPI uptake compared with low-grade IPMN and other benign cystic lesions. In dynamic imaging, menacing IPMN showed increasing time-activity curves followed by slow decrease afterward; time-activity curves of low-grade IPMN showed an immediate peak followed by rapid decrease for about 10 min and slower decrease for the rest of the time. Receiver-operating curves showed high sensitivity and specificity (area under the curve greater than 80%) of static and dynamic PET parameters for the differentiation of IPMN subtypes. Conclusion: ⁶⁸Ga-FAPI PET is a helpful new tool for the differentiation of menacing and low-grade IPMN and shows the potential to avoid unnecessary surgery for nonmalignant pancreatic IPMN.

Preoperative Predictive Features of Invasive Carcinoma Among Intraductal Papillary Mucinous Neoplasm of the Pancreas

OBJECTIVE

Noninvasive intraductal papillary mucinous neoplasms (IPMNs) theoretically do not metastasize. The purpose of this study is to preoperatively distinguish invasive carcinomas associated with IPMN from noninvasive IPMN.

METHODS

A total of 131 patients who underwent surgical resection for IPMN were retrospectively analyzed to identify the predictors of invasive carcinoma, based on the International Association of Pancreatology Consensus Guidelines.

RESULTS

Of the 131 patients, 29 (22%) had invasive carcinomas and 102 (78%) had noninvasive IPMN. An enhancing mural nodule (MN) greater than or equal to 5 mm, obstructive jaundice, an abrupt change in the caliber of the pancreatic duct (PD) with distal pancreatic atrophy, and lymphadenopathy were the significant predictors of invasive carcinoma in univariate analysis. The optimal cutoff value for the size of the enhancing MN to differentiate invasive carcinoma was 13 mm. In multivariate analysis, enhancing MN greater than or equal to 13 mm, obstructive jaundice, and an abrupt change in the PD caliber were the independent predictors. When all these factors were absent, only 17% were invasive carcinomas.

CONCLUSIONS

Enhancing MN greater than or equal to 13 mm, obstructive jaundice, and an abrupt change in the PD caliber were predictive factors for invasive carcinoma. Systematic lymph node dissection may be omitted when a high-risk patient has none of these factors.

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography to Detect Benign and Malignant Biliary Strictures

Background:

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method to detect pancreaticobiliary strictures. In this study, we aimed to evaluate the diagnostic performance of MRCP and detect sensitive and specific radiologic features in distinguishing malignant and benign pathologies.

Materials and Methods:

In this study, 50 patients with biliary obstruction and a confirmed diagnosis using histopathology were included. The pathologies were evaluated using MRCP which were categorized into malignant and benign strictures. The etiology of strictures was detected using histopathology and endoscopic retrograde cholangiopancreatography. The diagnostic performance of MRCP was calculated using SPSS software. P < 0.05 was considered statistically significant.

Results:

Of 50 patients, 23 patients (46%) had malignant strictures based on MRCP and histopathology. The sensitivity and specificity of MRCP to detect malignancy were 95.7% and 96.3%, respectively. The most sensitive MRCP features to detect malignancy were upstream biliary duct dilation, abrupt tapering, and the presence of a solid mass with sensitivity 100%, 95.7%, and 78.2%, respectively. The malignancy rate was significantly higher in the strictures with length >11.5 mm or wall thickness >2.75 mm (P < 0.05).

Conclusion:

MRCP is a sensitive method to differentiate malignant lesions from benign pathologies. A long and thick stricture with the presence of a solid mass, upstream biliary duct dilation, and abrupt tapering is highly suggestive of malignancy.

Cost-effectiveness analysis of including contrast-enhanced ultrasound in management of pancreatic cystic neoplasms

PURPOSE

Pancreatic cystic neoplasms (PCN) management consists of non-invasive imaging studies (CT, MRI), with a high resource burden. We aimed to determine the cost-effectiveness of including contrast-enhanced ultrasound (CEUS) in the management of PCN without risk features.

MATERIALS AND METHODS

By using a decision-tree model in a hypothetical cohort of patients, we compared management strategy including CEUS with the latest Fukuoka consensus, European and Italian guidelines. Our strategy for BD-IPMN/MCN < 1 cm includes 1 CEUS annually. For those between 1 and 2 cm, it includes CEUS 4 times/year during the first year, then 3 times/year for 4 years and then annually. For those between 2 and 3 cm, it comprises MRI twice/year during the first one, then alternating 2 CEUS and 1 MRI yearly.

RESULTS

CEUS surveillance is the dominant strategy in all scenarios. CEUS surveillance average cost is 1,984.72 €, mean QALY 11.79 and mean ICER 181.99 €. If willingness to pay is 30,000 €, 45% of patients undergone CEUS surveillance of BDIPMN/MCN < 1 cm would be within budget.

CONCLUSION

Guidelines strategies are very effective, but costs are relatively high from a policy perspective. CEUS surveillance may be a cost-effective strategy yielding a nearly high QALYs, an acceptable ICER, and a lower cost.

Clinical Utility and Limitation of Diagnostic Ability for Different Degrees of Dysplasia of Intraductal Papillary Mucinous Neoplasms of the Pancreas Using 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

Simple Summary

Elucidating risk factors for different degrees of dysplasia of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas is important in determining strategies for management. In this study, we searched for risk factors for different degrees of dysplasia of IPMNs. Our study indicated that there were no useful factors that significantly differentiated low-grade dysplasia and high-grade dysplasia; however, ¹⁸F-fluorodeoxyglucose–positron emission tomography/computed tomography is useful for differentiating between non-invasive and invasive IPMNs. Our results offer critical information that may determine surgical treatment strategies.

Abstract

The diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) uptake in the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas remains unclear. This study aimed to assess the role of FDG uptake in the diagnosis of different degrees of dysplasia of IPMNs. We retrospectively analyzed the following three points in 84 patients with IPMNs: (1) risk factors to predict high-grade dysplasia (HGD) and invasive carcinoma (INV); (2) the relationship between FDG uptake and glucose transporter 1 (GLUT-1) expression; and (3) the relationship between FDG uptake and the presence of mural nodules. The histopathological diagnosis was low-grade dysplasia (LGD) in 43 patients, HGD in 16, and INV in 25. The maximum standardized uptake value (SUV-max) was significantly higher in INV than in LGD/HGD (p < 0.0001, p = 0.0136). The sensitivity and specificity to discriminate INV from LGD/HGD were 80.0% and 86.2%, respectively, using the receiver operator characteristic curve, when the optimal cutoff score of SUV-max was set at 4.03. Those values were not different between HGD and LGD. More than half of HGD patients had low GLUT-1 expression. Taken together, FDG-PET/CT is useful in distinguishing between non-invasive and invasive IPMN. Our results offer critical information that may determine surgical treatment strategies.

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.

Magnetic resonance (MR) for mural nodule detection studying Intraductal papillary mucinous neoplasms (IPMN) of pancreas: Imaging-pathologic correlation

PURPOSE

Magnetic Resonance (MR) is recommended to diagnose Intraductal Papillary Mucinous Neoplasms (IPMN) and in the follow-up of borderline lesions. The purpose of this work is to evaluate the diagnostic accuracy of dynamic MR with Diffusion Weighted Imaging (DWI) in the identification of mural nodules of pancreatic IPMN by using pathological analysis as gold standard.

MATERIALS AND METHODS

Ninety-one preoperative MR with histopathological diagnosis of IPMN were reviewed by two radiologists. Presence, number and size of mural nodule, signal intensity of the nodule on T1-weighted imaging (T1-WI) after contrast medium administration and on DWI. Inter-observer agreement was evaluated.

RESULTS

Significant correlation (p < 0.0001) were found for presence of nodules > 5 mm on MR and pathological specimen, size and number of mural nodules evaluated on pathological review and degree of dysplasia, size and number of mural nodules evaluated on MR and tumoral dysplasia, presence of nodule > 5 mm with enhancement after contrast medium administration and hyperintensity on DWI and degree of dysplasia. Interobserver agreement was moderate for the presence of mural nodule (K = 0.56), for the presence of high signal intensity on DWI (K = 0.57) and enhancement of mural nodule (K = 0.58). Apparent Diffusion Coefficient (ADC) map histogram analysis showed a correlation between Entropy of the entire cystic lesion and the degree of dysplasia (p < 0.034).

CONCLUSIONS

MR with dynamic and DWI sequences was an accurate method for the identification of ≥ 5 mm solid nodules of the IPMNs and correlate with the lesion malignancy. Entropy, calculated from the histogram analysis of the IPMN ADC map, correlated with the lesion dysplasia.

Application of EUS-based techniques in the evaluation of pancreatic cystic neoplasms

Pancreatic cystic neoplasms (PCNs) are being detected increasingly frequently due to the widespread use of high-resolution abdominal imaging modalities. Some subtypes of PCNs have the potential for malignant transformation. Therefore, accurate diagnosis of PCNs is crucial to determine whether surgical resection or surveillance is the best management strategy. However, the current cross-section imaging modalities are not accurate enough to enable definite diagnoses. In the last decade, EUS-based techniques have emerged, aiming to overcome the limitations of standard cross-section imaging modalities. These novel EUS-based techniques were primarily designed to acquire distinct images to make radiological diagnoses, collect cyst fluid to undergo biochemical or molecular analyses, and obtain tissue to conclude the pathological diagnoses. In this article, we present a comprehensive and critical review of these emerging EUS techniques for the diagnosis of PCNs, with emphasis being placed on the advantages, feasibilities, diagnostic performances, and limitations of these novel techniques.

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.

Outcomes of limited resection for patients with intraductal papillary mucinous neoplasm of the pancreas: A single-center experience

BACKGROUND

/ObjectivesThe aim of this study was to clarify the oncological outcomes of patients with intraductal papillary mucinous neoplasm (IPMN) who underwent limited resection (LR).

METHODS

This retrospective study analyzed the data of 110 patients with IPMN. Patients with IPMN without a history of pancreatitis who had neither tumor infiltration nor regional lymph node swelling on imaging findings underwent LR. We assessed the oncological outcomes of LR for patients with IPMN by comparing the surgical outcomes of LR and standard resection.

RESULTS

LR was performed in 50 patients (45.5%), including duodenum-preserving pancreatic head resection (n = 31), middle-pancreatectomy (n = 12), spleen-preserving distal pancreatectomy (n = 3), total parenchymal pancreatectomy (n = 3), and partial resection (n = 1). In the LR group, 18 patients had postoperative complications of Clavien-Dindo classification ≥ IIIa. After histopathological examination, the presence of high-grade dysplasia (HGD) and invasive carcinoma (IC) were observed in nine and three patients, respectively, in the LR group, and eight and 22 patients, respectively, in the standard resection group. There was a significant difference in the histopathological diagnosis of IC between the two groups (p < 0.001). Finally, in the LR group, postoperative recurrences occurred in three patients, and the 5-, 10-, and 15-year disease-specific survival rates were all 97.0%.

CONCLUSIONS

For patients with IPMN judged to have no infiltrating lesions based on the detailed imaging examination, LR is acceptable and may be considered as an alternative to standard resection.

The efficacy of pancreatic juice cytology with liquid-based cytology for evaluating malignancy in patients with intraductal papillary mucinous neoplasm

Background

Pancreatic juice cytology (PJC) is a tool for diagnosing malignant intraductal papillary mucinous neoplasm (IPMN); however, the accuracy is insufficient using the conventional method. Liquid-based cytology (LBC) improves the cell recovery rate, and almost all cells can be evaluated. We evaluated the efficacy of PJC with LBC for malignant IPMN.

Methods

We retrospectively analyzed 90 patients with suspected malignant IPMN who underwent PJC before pancreatectomy. PJC with smear and LBC methods was conducted in 52 patients (between June 2003 to December 2011) and 38 patients (between January 2012 to December 2018). Based on the imaging studies, all of the patients were classified according to the international consensus guidelines for IPMN revised in 2017.

Results

Of the 90 patients, 43 (48%) had malignant IPMN (high-grade dysplasia or invasive carcinoma), and the remaining patients had non-malignant IPMN (intermediate- or low-grade dysplasia). LBC increased the accuracy of PJC for the diagnosis of malignant IPMN (smear method: 56% [29/52] vs. LBC method: 76% [29/38]; P = 0.044). In a multivariate analysis, LBC was a significant factor influencing the accurate diagnosis of PJC (odds ratio: 3.52; P = 0.021). Furthermore, LBC increased the accuracy of PJC for malignant IPMN in patients with worrisome features (smear method: 66% [19/29] vs. LBC method: 93% [14/15]; P = 0.043).

Conclusions

LBC increases the accuracy of PJC for diagnosing malignant IPMN compared with the conventional smear method.

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.

Surgical indication for intraductal papillary mucinous neoplasm without mural nodule ≥5 mm

BACKGROUND

In intraductal papillary mucinous neoplasm, a mural nodule ≥5 mm is an important predictor of malignancy. Surgical indication is less clear in cases of intraductal papillary mucinous neoplasm without mural nodule ≥5 mm. This is a retrospective study evaluating predictors of high-grade dysplasia or invasive intraductal papillary mucinous carcinoma for intraductal papillary mucinous neoplasm without mural nodule ≥5 mm.

METHODS

Among consecutive patients who underwent surgery for intraductal papillary mucinous neoplasm between 1999 and 2018, 174 had intraductal papillary mucinous neoplasm with mural nodule ≥5 mm (mural nodule[+] ≥5 mm group). The remaining 155 patients had intraductal papillary mucinous neoplasm but did not have mural nodule ≥5 mm: 24 patients with mural nodule <5 mm (mural nodule[+] <5 mm group) and 131 patients without mural nodule (mural nodule[-] group). We investigated predictors of high-grade dysplasia or invasive intraductal papillary mucinous neoplasm in cases of intraductal papillary mucinous neoplasm without mural nodule ≥5 mm.

RESULTS

The frequency of high-grade dysplasia invasive intraductal papillary mucinous neoplasm was significantly higher in the mural nodule(+) ≥5 mm group (87.4%) than in the mural nodule(+) <5 mm group (37.5%, P < .001) and mural nodule(-) group (45.0%, P < .001). However, frequency was not significantly different between mural nodule(+) <5 mm and mural nodule(-) groups (P = .494). Multivariate analysis showed three independent predictors of high-grade dysplasia invasive intraductal papillary mucinous carcinoma in intraductal papillary mucinous neoplasm without mural nodule ≥5 mm: branch cyst ≥40 mm (P = .038, odds ratio 3.704; 95% confidence interval, 1.075-12.821), positive cytology of pancreatic juice (P = .039, odds ratio 16.792; 95% confidence interval, 1.152-244.744), and carcinoembryonic antigen in pancreatic juice ≥30 mg/mL (P < .001, odds ratio 14.925; 95% confidence interval, 4.525-50.0).

CONCLUSION

For cases of intraductal papillary mucinous neoplasm without mural nodule ≥5 mm, large cysts, positive cytology of the pancreatic juice, and high levels of carcinoembryonic antigen in pancreatic juice may be useful to determine surgical indication, although further studies are needed to confirm these results.

New Model for Predicting Malignancy in Patients With Intraductal Papillary Mucinous Neoplasm

OBJECTIVE

To create a simple, objective model to predict the presence of malignancy in patients with intraductal papillary mucinous neoplasm (IPMN), which can be easily applied in daily practice and, importantly, adopted for any lesion types.

BACKGROUND

No predictive model for malignant IPMN has been widely applied in clinical practice.

METHODS

The clinical details of 466 patients with IPMN who underwent pancreatic resection at 3 hospitals were retrospectively analyzed for model development. Then, the model was validated in 664 surgically resected patients at 8 hospitals in Japan.In the preoperative examination, endoscopic ultrasonography (EUS) was considered to be essential to observe mural nodules in both the model development and external validation sets. Malignant IPMNs were defined as those with high-grade dysplasia and associated invasive carcinoma.

RESULTS

Of the 466 patients, 258 (55%) had malignant IPMNs (158 high-grade dysplasia, 100 invasive carcinoma), and 208 (45%) had benign IPMNs. Logistic regression analysis resulted in 3 variables (mural nodule size, main pancreatic duct diameter, and cyst size) being selected to construct the model. The area under the receiver operating characteristic curve (AUC) for the model was 0.763. In external validation sets, the pathological diagnosis was malignant and benign IPMN in 351 (53%) and 313 (47%) cases, respectively. For the external validation, the malignancy prediction ability of the model corresponded to an AUC of 0.725.

CONCLUSION

This predictive model provides important information for physicians and patients in assessing an individual's risk for malignancy and may help to identify patients who need surgery.

[Indications for the Surgical Management of Pancreatic Cystic Lesions]

A steady improvement in modern imaging as well as increasing age in society have led to an increasing number of cystic pancreatic tumours being detected. Pancreatic cysts are a clinically challenging entity because they span a broad biological spectrum and their differentiation is often difficult, especially in small tumours. Therefore, they require a differentiated indication for indication of surgery. To determine recommendations for the surgical indication in cystic tumours of the pancreas, a quality committee for pancreatic diseases of the German Society for General and Visceral Surgery performed a systematic literature search and created this review. Based on the current evidence, signs of malignancy and high-risk criteria (icterus due to cystic pancreatic duct obstruction in the bile duct, enhancing mural nodules ≥ 5 mm or solid components in the cyst or pancreatic duct ≥ 10 mm), as well as symptoms, are a surgical indication, independently of the cyst entity (except pseudocysts). If the entity of the pancreatic cyst is detectable by diagnostic imaging, all main duct IPMN and IPMN of the mixed type, all MCN > 4 cm and all SPN should be resected. SCN and branch-duct IPMN without worrisome features do not constitute an indication for surgery. The indication of operation in branch-duct IPMN with relative risk criteria and MCN < 4 cm is the subject of current discussions and should be individualised. By defining indication recommendations, the present work aims to improve the indication quality in cystic pancreatic tumours. However, the surgical indication should always be individualised, taking into account age, comorbidities and the patient's wishes.

MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY (MRCP) VERSUS ENDOSONOGRAPHY-GUIDED FINE NEEDLE ASPIRATION (EUS-FNA) FOR DIAGNOSIS AND FOLLOW-UP OF PANCREATIC INTRADUCTAL PAPILLARY MUCINOUS NEOPLASMS

Background:

Intraductal papillary mucinous tumor (IPMN) are being diagnosed with increasing frequency. Computerized tomography scanning is commonly used as the primary imaging modality before surgery nonetheless magnetic resonance cholangiopancreatography (MRCP) provides better characterization. Endosonography-guided fine needle aspiration (EUS-FNA) has emerged as a way to reach pathological diagnose.

Aim:

To compare results of both methods with surgical pathology findings for classification of IPMN.

Methods:

Thirty-six patients submitted to surgical resection with preoperative suspect of IPMN were submitted preoperatively to MRCP and EUS-FNA. Images obtained were analyzed according to a classification determined for each method. ROC curve was used for statistical analysis, that compared the images tests with the purpose of finding the best method for diagnosis and classification of IPMN.

Results:

Sixteen patients underwent pancreatoduodenectomy, 16 to subtotal pancreatectomy and only four laparotomy. Pathological diagnosis was IPMN (n=33) and pancreatic intraepithelial neoplasia type 2 (n=3). Twenty-nine revealed non-invasive neoplasia and invasive form in four patients. MRCP and EUS-FNA have correctly diagnosed and classified (type of IPMN), in 62.5% and 83.3% (p=0.811), the affected segment location in 69% and 92% (p=0.638) and identification of nodules and/or vegetation presence in 45% and 90% (p=0.5). Regarding to histopathological diagnosis by EUS-FNA the sensitivity was 83.3%; specificity was 100%; positive predictive value was 100%; negative predictive value was 33.3% and accuracy was 91.7%.

Conclusions:

There was no significant difference in the diagnosis of IPMN. However, EUS-FNA showed better absolute results than MRCP to identify nodule and/or vegetation.

Invasive intraductal papillary mucinous neoplasms of the pancreas: relationships between mural nodules detected on thin-section contrast-enhanced MDCT and invasive components

PURPOSE

To elucidate the relationships between mural nodules (MNs) and invasive components in patients with invasive intraductal papillary mucinous neoplasm (IPMN) on the basis of thin-section contrast-enhanced multidetector CT (CE-MDCT) and pathologic findings.

METHODS

This retrospective study included 28 patients with surgically confirmed invasive IPMN. Two radiologists independently evaluated the thin-section (1-mm section thickness, no overlap) triple-phase CE-MDCT images for MNs, invasive components, and the continuity between them using a five-point scale (confidence scores of 1-3 as negative, 4 and 5 as positive). Kappa statistic was used to evaluate interobserver agreement. The CE-MDCT findings were correlated with pathologic findings.

RESULTS

Interobserver agreement was good or excellent. MNs consisting of tumor cells were recognized in 12 (42.9%) of 28 patients with no discrepancy between the two radiologists. Invasive components were detected in 85.7% and 82.1% in the pancreatic parenchymal phase for radiologist 1 and 2, respectively, and recognized as hypoattenuating areas. Pathologic continuities between MNs and invasive components were confirmed in five (41.7%) of 12 patients with MNs and these were detected on CE-MDCT. When combined seven patients without continuities between MNs and invasive components and 16 patients without MNs, the invasive components pathologically derived from non-nodular low-height papillary epithelium in 23 (82.1%) of 28 patients.

CONCLUSIONS

The invasive components derived more often from low-height papillary epithelium without MN appearance on CE-MDCT than from MN. Careful attention should be paid to the existence of an invasive component even in the absence of an enhancing MN.

Prevalence of pancreatic cystic lesions detected by magnetic resonance imaging in the Chinese population

BACKGROUND AND AIM

Incidental pancreatic cystic lesions (PCLs) are being diagnosed more frequently. However, little is known about the prevalence of PCLs in the Chinese population. The aim of the study was to assess the crude prevalence of PCLs in individuals who underwent magnetic resonance imaging (MRI).

METHODS

Data from consecutive patients who underwent MRI without pancreatic indications were included. MRI images were reviewed for the presence of pancreatic cysts. The prevalence of PCLs and high-risk PCLs in different gender and age groups was calculated. To assess the crude prevalence, the prevalence and demographic data were standardized on the basis of Chinese national population data in 2017.

RESULTS

A total of 10 987 individuals were included (7344 men). Incidental PCLs were identified in 212 individual (128 men). The prevalence of PCLs was 1.93%, and PCLs were more often discovered in women (1.74% vs 2.31%, P = 0.043). Prevalence increased with age (r = 0.804, P < 0.001). The prevalence of high-risk PCLs was 0.12% (n = 13). Gender predominance and age distribution showed no difference between high-risk PCLs and low-risk PCLs (P = 0.234 and P = 0.855), but cysts located in the pancreatic head were more likely to develop into high-risk PCLs (P = 0.001). After data standardization, the crude prevalence of PCLs was 1.31%, and PCLs were more often discovered in women (1.11% vs 1.5%, P < 0.001). The crude prevalence of high-risk PCLs was 0.07%.

CONCLUSION

Pancreatic cystic lesions in the Chinese population are not rare. The prevalence of PCLs increased with age and is higher in the female population. The prevalence of high-risk PCLs should not be ignored.

Evaluating the malignant potential of intraductal papillary mucinous neoplasms of the pancreas: added value of non-enhanced endoscopic ultrasound to supplement non-enhanced magnetic resonance imaging

Purpose

To evaluate the diagnostic performance of combining non-enhanced magnetic resonance imaging (MRI) and non-enhanced endoscopic ultrasonography (EUS) for assessing the malignant potential of lesions in patients with intraductal papillary mucinous neoplasms of the pancreas (IPMNs).

Material and methods

Data from 38 patients histopathologically diagnosed with IPMN adenomas or IPMN adenocarcinomas were retrospectively analysed. Preliminary univariate and multivariate analyses were conducted to identify statistically significant associations. Three blinded radiologists evaluated the image sets to assess the diagnostic performance of combined use of non-enhanced MRI and EUS as opposed to non-enhanced MRI alone in distinguishing malignant from benign lesions. Observer performance and interobserver variability were determined using receiver-operating-characteristic curve analysis and weighted κ statistics.

Results

Multivariate analyses identified a significant difference between the abrupt change in the main pancreatic duct (MPD) calibre with distal pancreatic atrophy and the signal intensity of lesion-to-spinal cord ratio on MRI; a significant difference was observed in MPD size on EUS. Diagnostic performance assessments of the image sets did not differ significantly between the blinded radiologists.

Conclusions

The clinical utility of non-enhanced EUS may be attributive in evaluating IPMN that has already been evaluated by non-enhanced MRI.

European evidence-based guidelines on pancreatic cystic neoplasms

Evidence-based guidelines on the management of pancreatic cystic neoplasms (PCN) are lacking. This guideline is a joint initiative of the European Study Group on Cystic Tumours of the Pancreas, United European Gastroenterology, European Pancreatic Club, European-African Hepato-Pancreato-Biliary Association, European Digestive Surgery, and the European Society of Gastrointestinal Endoscopy. It replaces the 2013 European consensus statement guidelines on PCN. European and non-European experts performed systematic reviews and used GRADE methodology to answer relevant clinical questions on nine topics (biomarkers, radiology, endoscopy, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystic neoplasm, rare cysts, (neo)adjuvant treatment, and pathology). Recommendations include conservative management, relative and absolute indications for surgery. A conservative approach is recommended for asymptomatic MCN and IPMN measuring <40 mm without an enhancing nodule. Relative indications for surgery in IPMN include a main pancreatic duct (MPD) diameter between 5 and 9.9 mm or a cyst diameter ≥40 mm. Absolute indications for surgery in IPMN, due to the high-risk of malignant transformation, include jaundice, an enhancing mural nodule >5 mm, and MPD diameter >10 mm. Lifelong follow-up of IPMN is recommended in patients who are fit for surgery. The European evidence-based guidelines on PCN aim to improve the diagnosis and management of PCN.

Systematic review, meta-analysis, and a high-volume center experience supporting the new role of mural nodules proposed by the updated 2017 international guidelines on IPMN of the pancreas

BACKGROUND

Mural nodules (MNs) have a predominant role in the 2016 revision of the international guidelines on intraductal papillary mucinous neoplasms (IPMN) of the pancreas. The aim of this study was to evaluate MNs as predictors of invasive cancer (iCa) or high-grade dysplasia (HGD) in IPMNs and to investigate the role of MN size in risk prediction.

METHODS

A PRISMA-compliant systematic review of the literature and meta-analysis on selected studies were conducted. The random effect model was adopted, and the pooled SMD (standardized mean difference) obtained. The surgical series of IPMNs at a single high-volume institution was reviewed.

RESULTS

This review included 70 studies and 2297 resected IPMNs. MNs have a positive predictive value for malignancy of 62.2%. The meta-analysis suggested that MN size has a considerable effect on predicting IPMNs with both iCa or HGD with a mean SMD of 0.79. All studies included in the meta-analysis used contrast-enhanced endosonography (CE-EUS) to assess MNs. Due to the heterogeneity of the proposed thresholds, no reliable MN size cut-off was identified. Of 317 IPMNs resected at our institution, 102 (32.1%) had a preoperative diagnosis of MN. Multivariate analysis showed that MN is the only independent predictor of iCa and HGD for all types of IPMNs.

CONCLUSION

MNs are reliable predictors of iCa and HGD in IPMNs as proposed by the 2016 IAP guidelines. CE-EUS seems to be the best tool for characterizing size and has the best accuracy for predicting malignancy. Further studies should determine potential MN dimensional cut-offs.

Utility of Endoscopic Ultrasonography Screening for Small Pancreatic Cancer and Proposal for a New Scoring System for Screening

OBJECTIVES

This study aimed to evaluate the utility of endoscopic ultrasonography screening for small pancreatic cancer (PC) and propose a new simple scoring system for selecting individuals who should be screened.

METHODS

Risk factors or symptoms related to PC were tentatively divided into high- and low-grade risk groups based mainly on reported relative risk values. Numbers of risk factors were designated as risk scores. Endoscopic ultrasonography screening was performed for 632 individuals. We analyzed scores for PC detection prospectively, and risk factors and scores of PC patients retrospectively.

RESULTS

We detected 10 small malignant pancreatic neoplasms (size ≤20 mm; 8 PCs; 9 Tis or T1) and 14 advanced PCs. All small PCs and 95.5% of PCs were found in individuals with low-grade risk scores of at least 3 points (P) or high-grade risk scores of at least 1P. Both average risk scores were significantly higher in patients with small PCs (P ≤ 0.04). Cutoffs for low- and high-grade risk scores implying the presence of small PC and all PC were 3P and 1P, respectively. When subjects having one or both cutoff scores were screened, sensitivity and specificity were 100% and 64.4% for small PCs and 95.5% and 64.4% for all PCs.

CONCLUSION

Endoscopic ultrasonography screening combining new scoring is effective for detecting small PC.

Revisions of international consensus Fukuoka guidelines for the management of IPMN of the pancreas

The management of intraductal papillary mucinous neoplasm (IPMN) continues to evolve. In particular, the indications for resection of branch duct IPMN have changed from early resection to more deliberate observation as proposed by the international consensus guidelines of 2006 and 2012. Another guideline proposed by the American Gastroenterological Association in 2015 restricted indications for surgery more stringently and recommended physicians to stop surveillance if no significant change had occurred in a pancreatic cyst after five years of surveillance, or if a patient underwent resection and a non-malignant IPMN was found. Whether or not it is safe to do so, as well as the method and interval of surveillance, has generated substantial debate. Based on a consensus symposium held during the meeting of the International Association of Pancreatology in Sendai, Japan, in 2016, the working group has revised the guidelines regarding prediction of invasive carcinoma and high-grade dysplasia, surveillance, and postoperative follow-up of IPMN. As the working group did not recognize the need for major revisions of the guidelines, we made only minor revisions and added most recent articles where appropriate. The present guidelines include updated information and recommendations based on our current understanding, and highlight issues that remain controversial or where further research is required.

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.

Cystic pancreatic lesions: From increased diagnosis rate to new dilemmas

Cystic pancreatic lesions vary from benign to malignant entities and are increasingly detected on cross-sectional imaging. Knowledge of the imaging appearances of cystic pancreatic lesions may help radiologists in their diagnostic reporting and management. In this review, we discuss the morphologic classification of these lesions based on a diagnostic algorithm as well as the management of these lesions.