Predictive factors for malignancy in intraductal papillary-mucinous tumours of the pancreas

Imaging of the Pancreas

The evaluation of pancreatic lesions, from solid pancreatic masses to pancreatic cysts, remains a clinical challenge. Although cross-sectional imaging remains the cornerstone of the initial evaluation of an indeterminate pancreatic lesion, advances in imaging with the advent of endoscopic ultrasound scan, elastography, contrast-enhanced endoscopic ultrasound scan, and probe-based confocal laser endomicroscopy have allowed us to visualize the pancreas in even higher resolution and diagnose premalignant and malignant lesions of the pancreas with improved accuracy. This report reviews the range of imaging tools currently available to evaluate pancreatic lesions, from solid tumors to pancreatic cysts.

Clinicopathological Meaning of Size of Main-Duct Dilatation in Intraductal Papillary Mucinous Neoplasm of Pancreas: Proposal of a Simplified Morphological Classification Based on the Investigation on the Size of Main Pancreatic Duct

BACKGROUND

The 2012 consensus guideline on intraductal papillary mucinous neoplasm of the pancreas (IPMN) described a three-stage criteria involving main pancreatic duct (MPD) size with definitions of malignancy relevant for treatment decisions. Re-evaluation and simplification of this classification for clinicians are warranted.

METHODS

Data from the Seoul National University Hospital of 375 consecutive patients with pathology-confirmed IPMN after surgery were analyzed. The association between clinicopathologic characteristics of IPMN and MPD size was assessed. The cut-off value of MPD size for a current definition of malignancy prediction was calculated.

RESULTS

Diagnostic accuracy for malignancy was highest when the cut-off value of MPD size was 7 mm (area under the curve=0.7126). Dichotomizing IPMN into MPD≤7 mm versus MPD> mm, patient age (p=0.039), sex (p=0.001), presence of mural nodule (p<0.001), and invasiveness risk (13.2 vs. 39.8%, p<0.001) resulted in significantly different results. Mural nodule-negative patients with MPD>7 mm had a significantly lower 5-year survival rate than those with MPD≤7 mm (78.4 vs. 91.4%, p=0.006). Among patients with MPD size≤7 mm, elevated serum CA 19-9 and mural nodule were independent risk factors of malignancy. Patients with MPD size≤7 mm without these risk factors had malignancy risk of 2.6%.

CONCLUSION

Using the definition of malignancy provided in the 2012 guideline, the MPD size> mm criterion was statistically driven. The current morphologic classification of IPMN can be simplified as branch-duct-predominant IPMN (MPD≤7 mm)' and main-duct-predominant IPMN (MPD> mm). Patients who are determined to have main-duct-predominant IPMN and branch-duct-predominant IPMN with elevated serum CA 19-9 or mural nodule are recommended to undergo surgical treatment.

Pancreatic Cysts

Pancreatic cysts are more common than before, largely because of widespread abdominal imaging. Pancreatic cystic neoplasms (PCN) are relevant to risk selection on 2 counts: they constitute more than 50% of all pancreatic cysts and, in contrast to the other 2 cyst types, are capable of malignant transformation. The majority of PCNs are benign at time of diagnosis and will follow a benign course. The challenge is to identify those PCNs that are malignant or will undergo malignant transformation with time. The purpose of this article is to provide pointers that can help meet this challenge while also summarizing the ongoing debate about their optimal management.

Effectiveness of contrast-enhanced endoscopic ultrasound for detecting mural nodules in intraductal papillary mucinous neoplasm of the pancreas and for making therapeutic decisions

Background and Objectives:

There have been few studies to date evaluating the effectiveness of contrast-enhanced endoscopic ultrasound (CE-EUS) for detecting mural nodules in patients with branch duct-type intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas. We aim to evaluate the effectiveness of CE-EUS for detecting mural nodules in BD-IPMN.

Patients and Methods:

Of the 427 BD-IPMN patients, 21 patients (4.9%) in whom the presence of mural nodules was suggested by CE computed tomography (CT) or magnetic resonance imaging (MRI), or in whom the presence of nodule-like lesions as shown by fundamental EUS, were examined by CE-EUS.

Results:

The mean diameter of cystic lesions was 29.8 ± 12.8 mm. The mean diameter of mural nodules was 9.5 ± 5.7 mm. BD-IPMN was detected in the pancreatic head in 16 cases, pancreatic body in 2 cases, and pancreatic tail in 3 cases. The mean follow-up period was 17.2 ± 11.9 months. The detection rates of mural nodule-like lesions in BD-IPMN patients on CT, MRI, and fundamental EUS were 36.8%, 63.2%, and 100%, respectively. The detection rates of true mural nodules in BD-IPMN patients on CT, MRI, and fundamental EUS were 85.7%, 71.4%, and 100%, respectively. The echo levels of mural nodule-like lesions on fundamental EUS were hyperechoic in 6 patients, isoechoic in 9 patients, and hypoechoic in 6 patients. The final diagnosis was mucus lumps in 14 patients and mural nodules in 7 patients. The contrast patterns observed were avascular, isovascular, and hypervascular in 14, 3, and 4 patients, respectively. No patients showed a hypovascular pattern. Fourteen patients showing an avascular pattern were diagnosed as having mucus lumps, and they were able to avoid surgical resection. Of the 7 patients who were diagnosed as having mural nodules, 5 underwent surgical resection. The pathological findings were adenocarcinoma in 2 patients and adenoma in 3 patients. Of the 3 adenoma patients, fundamental EUS demonstrated a hypoechoic area in 1 patient and an isoechoic area in 2 patients. Of the 2 adenocarcinoma patients, 1 each showed a hypoechoic area and a hyperechoic area. It was difficult to distinguish between patients with adenoma and patients with adenocarcinoma using the echo levels obtained from fundamental EUS.

Conclusions:

CE-EUS may be useful for avoiding the overdiagnosis of BD-IPMN with mural nodule-like lesions. However, it has difficulty in distinguishing between clearly benign and malignant lesions in BD-IPMN.

Imaging patterns of intraductal papillary mucinous neoplasms of the pancreas: an illustrated discussion of the International Consensus Guidelines for the Management of IPMN

Intraductal papillary mucinous neoplasms (IPMN) are being diagnosed with increasing frequency, necessitating an algorithm to help stratify patients into low- and high-risk groups, for follow-up versus more invasive evaluation. New evidence concerning their natural history and overall risk of malignancy has emerged since the 2006 International Association of Pancreatology consensus guidelines, prompting an update in 2012, that distinguishes radiologic 'worrisome features' from 'high-risk stigmata'. The aim of this article is to illustrate, with case examples, the variable imaging patterns of IPMN and how their radiologic features, such as cyst size and mural nodules, are interpreted in the context of the new 2012 guidelines. The 2012 and 2006 guidelines will be compared and discussed with reference to additional studies that have since been published. Despite these guidelines, lingering uncertainty remains about the natural history of IPMN, a source of unease to both radiologists and referring clinicians alike, mandating further refinement of clinical and radiologic parameters predictive of malignancy. Emerging data regarding the risk of extrapancreatic malignancy, as well as synchronous or metachronous pancreatic ductal adenocarcinoma remote in location from a branch duct IPMN are also reviewed. With the expanding research and evolving understanding of this clinicopathologic entity across the globe, radiologists will continue to play an important role in the management of patients with IPMN.

A Revised Classification System and Recommendations From the Baltimore Consensus Meeting for Neoplastic Precursor Lesions in the Pancreas

International experts met to discuss recent advances and to revise the 2004 recommendations for assessing and reporting precursor lesions to invasive carcinomas of the pancreas, including pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm, and other lesions. Consensus recommendations include the following: (1) To improve concordance and to align with practical consequences, a 2-tiered system (low vs. high grade) is proposed for all precursor lesions, with the provision that the current PanIN-2 and neoplasms with intermediate-grade dysplasia now be categorized as low grade. Thus, "high-grade dysplasia" is to be reserved for only the uppermost end of the spectrum ("carcinoma in situ"-type lesions). (2) Current data indicate that PanIN of any grade at a margin of a resected pancreas with invasive carcinoma does not have prognostic implications; the clinical significance of dysplasia at a margin in a resected pancreas with IPMN lacking invasive carcinoma remains to be determined. (3) Intraductal lesions 0.5 to 1 cm can be either large PanINs or small IPMNs. The term "incipient IPMN" should be reserved for lesions in this size with intestinal or oncocytic papillae or GNAS mutations. (4) Measurement of the distance between an IPMN and invasive carcinoma and sampling of intervening tissue are recommended to assess concomitant versus associated status. Conceptually, concomitant invasive carcinoma (in contrast with the "associated" group) ought to be genetically distinct from an IPMN elsewhere in the gland. (5) "Intraductal spread of invasive carcinoma" (aka, "colonization") is recommended to describe lesions of invasive carcinoma invading back into and extending along the ductal system, which may morphologically mimic high-grade PanIN or even IPMN. (6) "Simple mucinous cyst" is recommended to describe cysts >1 cm having gastric-type flat mucinous lining at most minimal atypia without ovarian-type stroma to distinguish them from IPMN. (7) Human lesions resembling the acinar to ductal metaplasia and atypical flat lesions of genetically engineered mouse models exist and may reflect an alternate pathway of carcinogenesis; however, their biological significance requires further study. These revised recommendations are expected to improve our management and understanding of precursor lesions in the pancreas.

Branch duct intraductal papillary mucinous neoplasm of the pancreas: single-center experience with 324 patients who underwent surgical resection

Backgrounds/Aims

International treatment guidelines for branch duct intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas have been proposed, for features associated with malignancy and invasiveness. We investigated the clinicopathological characteristics that are predictive of malignancy or invasiveness and disease recurrence.

Methods

A review of 324 patients with resected and pathologically confirmed BD-IPMN, between March 1997 and December 2013, was conducted.

Results

There were 144 (44.4%) low grade dysplasia (LGD), 138 (42.6%) intermediate grade dysplasia (IMGD), 17 (5.3%) high grade dysplasia (HGD), and 25 (7.7%) invasive carcinoma (invIPMC) cases. The 5-year survival rates were 98.1% for LGD, 95.3% for IMGD, 100% for HGD, and 71.8% for invIPMC. Through a univariate analysis, the male sex was associated with malignancy, and CA19-9 was related to both malignant and invasive IPMN. The high risk or worrisome features of the international guidelines were associated with both malignant and invasive IPMN: the total bilirubin of the head/uncinate lesion, tumor size, mural nodule, and the size of the main pancreatic duct (MPD). Through a multivariate analysis, the male sex, elevated CA19-9, mural nodule, and dilated MPD diameter were independently correlated with the malignant IPMN. The elevated CA19-9 and dilated MPD diameter were also correlated with invasive carcinoma. The patient age and the initial pathological diagnosis were strongly associated with disease recurrence following surgical resection.

Conclusions

The high risk or worrisome features in the current treatment guidelines for BD-IPMN are confined to the morphological characteristics of the disease. Patient factors and biological features should also be considered in order to develop optimal therapeutic or surveillance strategies.

Intraductal Papillary Mucinous Adenocarcinoma of the Pancreas: Clinical Outcomes, Prognostic Factors, and the Role of Adjuvant Therapy

BACKGROUND

Intraductal papillary mucinous adenocarcinoma (IPMCs) occur more frequently in main-duct intraductal papillary mucinous neoplasms.

METHODS

Review of the literature.

RESULTS

The prognosis of IPMCs depends on its histopathological subtype: colloid IPMCs have superior survival rates mainly secondary to more favorable pathological features, whereas tubular IPMCs have survival outcomes similar to that of conventional pancreatic adenocarcinomas. The epithelial background plays an equally important role in defining the biology of IPMCs: gastric IPMC subtypes demonstrate an overall worse survival outcome when compared to intestinal, pancreatobiliary, and oncocytic subtypes. Lymph node involvement is one of the strongest predictors of survival in IPMC, with a decreasing overall survival as the lymph node ratio increases. There is little evidence to support adjuvant chemoradiation in patients with IPMC.

CONCLUSION

Our current understanding of IPMC biology based on histopathological and epithelial background subtypes as well as clinicopathological predictors should influence patient counseling and selection for adjuvant therapy.

Increased risk of second malignancy in pancreatic intraductal papillary mucinous tumors: Review of the literature

AIM: To analyze the available evidence about the risk of extrapancreatic malignancies and pancreatic ductal adenocarcinoma associated to pancreatic intraductal papillary mucinous tumors (IPMNs).

METHODS: A systematic search of literature was undertaken using MEDLINE, EMBASE, Cochrane and Web-of-Science libraries. No limitations for year of publication were considered; preference was given to English papers. All references in selected articles were further screened for additional publications. Both clinical series and Literature reviews were selected. For all eligible studies, a standard data extraction form was filled in and the following data were extracted: study design, number of patients, prevalence of pancreatic cancer and extrapancreatic malignancies in IPMN patients and control groups, if available.

RESULTS: A total of 805 abstracts were selected and read; 25 articles were considered pertinent and 17 were chosen for the present systematic review. Eleven monocentric series, 1 multicentric series, 1 case-control study, 1 population-based study and 3 case report were included. A total of 2881 patients were globally analyzed as study group, and the incidence of pancreatic cancer and/or extrapancreatic malignancies ranged from 5% to 52%, with a mean of 28.71%. When a control group was analyzed (6 papers), the same incidence was as low as 9.4%.

CONCLUSION: The available Literature is unanimous in claiming IPMNs to be strongly associated with pancreatic and extrapancreatic malignancies. The consequences in IPMNs management are herein discussed.

Risk factors for malignant progression of intraductal papillary mucinous neoplasms

BACKGROUND

Intraductal papillary mucinous neoplasms of the pancreas are increasingly diagnosed. Due to their malignant potential, greater understanding of their nature is required.

AIMS

Define risk factors for malignancy in intraductal papillary mucinous neoplasms.

METHODS

An international, multicentre study was performed in Europe and the United States. Clinical databases were reviewed for patients with intraductal papillary mucinous neoplasms diagnosis.

RESULTS

Of 1126 patients, 84 were diagnosed with invasive carcinoma/high-grade dysplasia and were compared to the rest of the cohort. Multivariate logistic analysis showed a statistically significant association between cancer/high-grade dysplasia and the variables smoking history (OR 1.9, 95% CI [1.1-3.1]), body mass index (OR 1.1, 95% CI [1-1.1]), symptoms (OR 3.4, 95% CI [1.9-6]), jaundice (OR 0.1, 95% CI [0-0.3]), and steatorrhea (OR 0.3, 95% CI [0.1-0.8]). Univariate analysis showed no association between malignancy and the cyst number/location (p=0.3 and p=0.5, respectively) although a strong association was shown for cyst size (p<0.001). The presence and size of nodules (p<0.01) and main duct involvement (p<0.001) were also strongly related with malignancy.

CONCLUSION

The presence of jaundice and steatorrhea, smoking, high body mass index, and imaging features such as cyst size, main duct involvement, and the presence and size of mural nodules are associated with high-grade neoplasia in intraductal papillary mucinous neoplasms.

The genetic classification of pancreatic neoplasia

Cancer is caused by the accumulation of inherited and/or acquired alterations in specific genes. The recent decline in the cost of DNA sequencing has allowed tumor sequencing to be conducted on a large scale, which, in turn, has led to an unprecedented understanding of the genetic events that drive neoplasia. This understanding, when integrated with meticulous histologic analyses and with clinical findings, has direct clinical implications. The recent sequencing of all of the major types of cystic and noncystic neoplasms of the pancreas has revealed opportunities for molecular diagnoses and for personalized treatment. This review summarizes the results from these recent studies focusing on the clinical relevance of genomic data.

Smoking is not associated with severe dysplasia or invasive carcinoma in resected intraductal papillary mucinous neoplasms

INTRODUCTION

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are precursor lesions that progress to invasive cancer through progressively worsening dysplasia. Although smoking is an established risk factor for pancreatic adenocarcinoma, potential associations with IPMN grade of dysplasia remain unclear.

METHODS

Pancreatic resections for IPMN from 1995 to 2013 were retrospectively reviewed. A total of 446 patients in which the smoking status was documented were identified.

RESULTS

Smoking history was positive in 47% of patients. Of smokers, 50% had branch-duct, 14% had main-duct, and 36% had mixed-type IPMN. Patients with main-duct IPMN were more commonly smokers (65%), compared to smoking history in 46% with mixed and 44% with branch-duct IPMN (p = 0.03). High-grade dysplasia occurred in 25% of smokers and 21% of nonsmokers (p = 0.32), and invasive carcinoma in 25% of smokers and 25% nonsmokers (p = 0.95). On multivariate analysis, duct size was independently associated with high-grade dysplasia (OR = 3.17, 95% CI = 1.79-5.64, p < 0.001). Presence of mural nodules (OR = 3.34, 95% CI = 1.82-6.12, p < 0.001), duct size (OR = 3.87, 95% CI = 2.21-6.75, p < 0.001), and symptoms (OR = 7.10, 95% CI = 3.80-13.08, p < 0.001), but not smoking history (OR = 1.10, 95% CI = 0.64-1.88, p = 0.73), were independent predictors of invasive carcinoma. Median overall survival was 70 months for smokers and 88 months for nonsmokers (p = 0.68).

CONCLUSION

Positive smoking history correlated with duct type classification but does not appear to be a risk factor for harboring high-grade dysplasia or invasive carcinoma in IPMNs.

Demographic features and natural history of intermediate-risk multifocal versus unifocal intraductal papillary mucinous neoplasms

OBJECTIVES

This study compares the progression of multifocal (MF) intraductal papillary mucinous neoplasms (IPMNs) to unifocal (UF) lesions.

METHODS

We performed a retrospective review of demographics, risk factors, and cyst characteristics of a prospectively maintained database of 999 patients with pancreatic cysts. Patients included had IPMN under surveillance for 12 months or more. Those with high-risk stigmata were excluded. Cyst size progression and development of worrisome features were compared between MF and UF cohorts. We evaluated whether the dominant cyst in MF-IPMN had more significant growth than did the other cysts.

RESULTS

Seventy-seven patients with MF-IPMN and 54 patients with UF-IPMN, with mean follow-up of 27 and 34 months, met the criteria. There were no significant differences between demographics, risk factors, or initial cyst sizes. Fifty-seven percent of MF dominant cysts and 48% of UF cysts increased in size (P = 0.31). Progression in MF was more likely in the dominant cyst (P < 0.05). There were no significant differences in the development of mural nodules or increase in cyst size to more than 3 cm.

CONCLUSIONS

Demographics of both cohorts were similar, as was the overall incidence of worrisome features. Because meaningful size progression primarily occurred in the dominant cyst, our findings support surveillance based on the dominant cyst in MF disease.

Validation of a nomogram for predicting the probability of carcinoma in patients with intraductal papillary mucinous neoplasm in 180 pancreatic resection patients at 3 high-volume centers

OBJECTIVE

We previously published a nomogram for prediction of carcinoma in patients with intraductal papillary mucinous neoplasm (IPMN). The objective of the current study was to validate this nomogram in an external cohort of patients at multiple institutions.

METHODS

The clinical details of 180 patients with IPMN who underwent a pancreatic resection at 3 hospitals were collected. Four significant predictive factors (sex, lesion type, nodule height, and pancreatic juice cytology) were analyzed.

RESULTS

Of the 180 patients, 66 (36.7%) had a main pancreatic duct-type IPMN and 114 (63.3%) had a branch pancreatic duct-type IPMN. The final pathological diagnosis was benign IPMN in 95 (52.8%) patients and malignant IPMN in 85 (47.2%) patients. The area under the receiver operating characteristic curve for the model was 0.760. The area under the receiver operating characteristic curve of the IPMN nomogram for prediction of malignancy was 0.747 in main pancreatic duct-type IPMN and 0.752 in branch pancreatic duct-type IPMN. The sensitivity and specificity of the model were 80.0% and 57.9%, respectively, when the predictive probability of more than 10% was used to indicate the presence of carcinoma.

CONCLUSIONS

This nomogram for predicting the probability of carcinoma in patients with IPMN was accurate in an external validation patient cohort.

Pancreatic cystic neoplasms: Review of current knowledge, diagnostic challenges, and management options

Pancreatic cystic lesions are being detected with increasing frequency, largely due to advances in cross-sectional imaging. The most common neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, solid pseudopapillary neoplasms, and cystic pancreatic endocrine neoplasms. Computed tomography (CT), magnetic resonance imaging (MRI), and endoscopic ultrasound (EUS) are currently used as imaging modalities. EUS-guided fine needle aspiration has proved to be a useful diagnostic tool, and enables an assessment of tumor markers, cytology, chemistries, and DNA analysis. Here, we review the current literature on pancreatic cystic neoplasms, including classification, diagnosis, treatment, and recommendations for surveillance. Data for this manuscript was acquired via searching the literature from inception to December 2014 on PubMed and Ovid MEDLINE.

Outcomes of nonresected main-duct intraductal papillary mucinous neoplasms of the pancreas

AIM: To compare characteristics and outcomes of resected and nonresected main-duct and mixed intraductal papillary mucinous neoplasms of the pancreas (IPMN).

METHODS: Over a 14-year period, 50 patients who did not undergo surgery for resectable main-duct or mixed IPMN, for reasons of precluding comorbidities, age and/or refusal, were compared with 74 patients who underwent resection to assess differences in rates of survival, recurrence/occurrence of malignancy, and prognostic factors. All study participants had dilatation of the main pancreatic duct by ≥ 5 mm, with or without dilatation of the branch ducts. Some of the nonsurgical patients showed evidence of mucus upon perendoscopic retrograde cholangiopancreatography or endoscopic ultrasound and/or after fine needle aspiration. For the surgical patients, pathologic analysis of resected specimens confirmed a diagnosis of IPMN with involvement of the main pancreatic duct or of both branch ducts as well as the main pancreatic duct. Clinical and biologic follow-ups were conducted for all patients at least annually, through hospitalization or consultation every six months during the first year of follow-up, together with abdominal imaging analysis (magnetic resonance cholangiopancreatography or computed tomography) and, if necessary, endoscopic ultrasound with or without fine needle aspiration.

RESULTS: The overall five-year survival rate of patients who underwent resection was significantly greater than that for the nonsurgical patients (74% vs 58%; P = 0.019). The parameters of age (< 70 years) and absence of a nodule were associated with better survival (P < 0.05); however, the parameters of main pancreatic duct diameter > 10 mm, branch duct diameter > 30 mm, or presence of extra pancreatic cancers did not significantly influence the prognosis. In the nonsurgical patients, pancreatic malignancy occurred in 36% of cases within a mean time of 33 mo (median: 29 mo; range: 8-141 mo). Comparison of the nonsurgical patients who experienced disease progression with those who did not progress showed no significant differences in age, sex, symptoms, subtype of IPMN, or follow-up period; only the size of the main pancreatic duct was significantly different between these two sub-groups, with the nonsurgical patients who experienced progression showing a greater diameter at the time of diagnosis (> 10 mm).

CONCLUSION: Patients unfit for surgery have a 36% greater risk of developing pancreatic malignancy of the main-duct or mixed IPMN within a median of 2.5 years.

A large mural nodule in branch duct intraductal papillary mucinous adenoma of the pancreas: a case report

Indications for resection of branch duct intraductal papillary mucinous neoplasms (IPMNs) remain controversial because of their low tendency to be malignant. Surgical resection should be recommended if any factors indicating malignancy are present. However, preoperative differentiation between benign and malignant tumors is very difficult, especially in cases of branch duct IPMNs. We herein report a case of branch duct intraductal papillary mucinous adenoma (IPMA) of the pancreas with a large mural nodule of 25 mm. A 74-year-old woman was admitted for examination and treatment for a cystic tumor in the head of the pancreas. Magnetic resonance cholangiopancreatography and computed tomography showed a cystic lesion, 50 mm in diameter, with an irregular mural nodule in the pancreatic head. Endoscopic ultrasonography demonstrated a multicystic tumor connected with the main pancreatic duct (MPD). The mural nodule had a diameter of 18 mm, and the MPD had a slight dilation of 6 mm. These findings suggested a high potential for malignancy. The patient underwent pancreaticoduodenectomy with lymph node dissection. The excised pancreas showed multiple cysts located in the branch pancreatic duct with a maximum diameter of 75 mm. The mural nodule had a maximum diameter of 25 mm. The tumor was diagnosed as an IPMA by pathological examination. After operation, the patient was discharged without any complications. Two years after resection, the patient remains in remission with no evidence of tumor recurrence.

Interobserver agreement for detection of malignant features of intraductal papillary mucinous neoplasms of the pancreas on MDCT

OBJECTIVE

The purpose of this retrospective study was to measure interobserver agreement in the assessment of malignant imaging features of intraductal papillary mucinous neoplasms (IPMNs) on MDCT.

MATERIALS AND METHODS

Pancreatic protocol CT studies were reviewed for 84 patients with resected IPMNs. Maximal diameter of the dominant cyst, presence of a mural nodule, presence of a solid component, and diameters of the main pancreatic duct (MPD) and common bile duct (CBD) were measured by four radiologists independently. In each patient, the IPMN was classified into one of three types: main duct, branch duct, or mixed IPMN. Interobserver agreement of lesion features was examined using the intraclass correlation coefficient (ICC) for continuous features and Fleiss kappa for categorical features.

RESULTS

The final dataset included 55 branch duct IPMNs, nine main duct IPMNs, and 20 mixed IPMNs. Moderate agreement (ĸ = 0.458; 95% CI, 0.345-0.564) was observed in assigning branch duct, main duct, or mixed IPMN subtypes. Measurement agreement was substantial to excellent for dominant cyst (ICC = 0.852; 95% CI, 0.777-0.907), MPD (0.753, 0.655-0.837), and CBD (0.608, 0.463-0.724) but only fair to moderate for the detection of the presence of mural nodule (ĸ = 0.284, 0.125-0.432) or solid component (ĸ = 0.405, 0211-0.577).

CONCLUSION

Substantial to excellent interobserver agreement in the measurement of cyst diameter, MPD, and CBD support their use for characterizing malignant features of IPMN on MDCT. However, the subjective interpretation of the presence of solid components and mural nodules by individual radiologists was more variable.

Importance of luminal membrane mesothelin expression in intraductal papillary mucinous neoplasms

The present study demonstrated that luminal membrane mesothelin expression is a reliable prognostic factor in gastric cancer. Intraductal papillary mucinous neoplasms (IPMNs) often exhibit a spectrum of dysplasia, ranging between adenoma and carcinoma. Therefore, an immunohistochemical analysis of mesothelin expression in IPMN was performed in the present study, focusing on the localization of mesothelin. IPMNs were classified into two groups, IPMNs associated with invasive carcinoma and low-high (L-H) grade dysplasias. The tumors were classified as mesothelin-positive or -negative and in the mesothelin-positive cases, the localization of mesothelin was evaluated as luminal membrane- or cytoplasmic-positive. Among the 37 IPMNs, mesothelin expression was observed in 21 samples (56.8%), including 46.2% (12 out of 26) of the L-H dysplasia and 81.8% (9 out of 11) of the invasive carcinoma samples (P=0.071). Luminal membrane localization was observed in 10 samples (27%), including 15.4% (4/26) of the L-H dysplasia samples and 54.5% (6 out of 11) of the invasive carcinoma samples (P=0.022). Six patients experienced post-operative recurrence, with five of the recurrent tumors exhibiting mesothelin expression and all six exhibiting luminal membrane localization. It was concluded that immunohistochemical examinations for mesothelin expression and localization are clinically useful for prognostic assessments and decision making regarding further treatment subsequent to surgical procedures in patients with IPMN.

Favorable response after gemcitabine-radiotherapy for invasive pancreatic intraductal papillary mucinous neoplasm: a case report

The efficacy of chemoradiotherapy for invasive pancreatic ductal carcinoma derived from an intraductal papillary mucinous neoplasm (IPMN) has not been established. The subject of the present report was a 53-year-old man admitted for the treatment of IPMN. The tumor, located in the pancreatic body, was of the mixed type of IPMN, and it involved the branch duct, where it was 38 mm in diameter, and the main duct, where it was 6 mm in diameter. Distal pancreatectomy was performed and the postoperative course was uneventful; however, histopathologic diagnosis revealed invasive ductal carcinoma with a positive surgical margin in the pancreatic duct. Although total pancreatectomy was recommended, chemoradiotherapy (50.4-Gy irradiation and gemcitabine) was preferred by the patient. At 9-month follow up, computed tomography and magnetic resonance imaging showed a cystic mass at the surgical margin of the pancreas. Endoscopic ultrasonography showed a 44-mm cystic lesion with nodules in the remnant pancreas, on the basis of which he underwent total pancreatectomy. Pathologic examination of the resected specimen revealed absence of the epithelium at the surgical margin of the main pancreatic duct, and malignant cells were not detected.

Noninvasive intraductal papillary mucinous neoplasms and mucinous cystic neoplasms: recurrence rates and postoperative imaging follow-up

BACKGROUND

Although surveillance guidelines for resected invasive mucinous neoplastic cysts are well-established, those for noninvasive cysts are not defined. We used our experience with resected noninvasive mucinous neoplastic cysts to define recurrence rates and the optimal frequency of postoperative imaging follow-up.

METHODS

We reviewed the medical records of 134 patients with resected, pathologically confirmed noninvasive mucinous neoplasms between 2002 and 2012. Demographics, comorbidities, cyst characteristics, and recurrence were evaluated. Survival analysis was used to estimate the distribution of time to recurrence and regression models were used to investigate factors associated with recurrence.

RESULTS

Eighty-seven patients with intraductal papillary mucinous neoplasms (IPMNs) were compared with 47 patients with mucinous cystic neoplasms (MCNs). Those with MCNs were more often females (P = .001), significantly younger (P = .001), more symptomatic (P = .009), and had cysts more often located in the tail (P < .001). Median follow-up was 42 months. Recurrence rates for IPMNs were 0%, 5%, and 10% versus 0% for MCNs respectively at postoperative years 1, 2, and 3 (P = .014). On multivariable analysis, size >3 cm (P = .027), higher grade dysplasia (P = .043), and positive resection margins (P < .001) were significantly associated with recurrence.

CONCLUSION

Resected noninvasive IPMNs with moderate- or high-grade dysplasia and negative resection margins require imaging follow-up every 2 years, given the 16% overall recurrence rate. Although the follow-up interval for noninvasive, low-grade, dysplastic IPMNs with negative margins could be lengthened, all noninvasive IPMNs having positive margins require yearly follow-up at the minimum. Resected noninvasive MCNs--irrespective of grade and margin status--do not require surveillance, although the development of branch duct-IPMNs in the remnant pancreas can be investigated in the long term at the discretion of the provider.

Invasive carcinoma derived from "flat type" branch duct intraductal papillary mucinous neoplasms of the pancreas: impact of classification according to the height of mural nodule on endoscopic ultrasonography

BACKGROUND

It has been reported that many branch duct intraductal papillary mucinous neoplasms (BD-IPMN) with a mural nodule (MN) reveal adenocarcinomas. On the other hand, invasive cancer derived from BD-IPMN without MN on endoscopic ultrasound (EUS) also exists. The aim of this study was to elucidate the clinicopathological features of invasive cancer derived from BD-IPMN without MN on EUS.

METHODS

Twenty-one patients pathologically diagnosed with invasive cancer derived from BD-IPMN were included in this study.

RESULTS

Based on the height of MNs on EUS, the subjects could be clearly classified as 12 patients whose background BD-IPMNs had high MNs (nodule-forming type IPMN) and nine whose background BD-IPMNs showed no MNs (flat type IPMN). The background BD-IPMN of the 12 patients with nodule-forming type IPMN were non-gastric type. On the other hand, the background BD-IPMN of the nine patients with flat type IPMN was gastric type. The recurrence rate was higher (33% vs. 67%) and the 5-year survival was worse (76% vs. 33%) in flat type IPMN.

CONCLUSIONS

There may be a pathway for the development of invasive cancer without the formation of an MN in BD-IPMN, and attention should be paid even to the patients with BD-IPMN which does not present an MN.

Incidental pancreatic cysts: role of magnetic resonance imaging

The widespread adoption of multidetector computed tomography and magnetic resonance imaging (MRI) for evaluation of intraabdominal pathology has resulted to a steady increase in the number of incidentally discovered pancreatic cysts in clinical practice during the last decades. The differential diagnosis of these cysts is broad including pseudocysts, serous cystic neoplasms, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms. The MRI has an important role both in the initial characterization of incidentally detected pancreatic cysts and the follow-up of these lesions and has become an integral part of the diagnostic algorithm for pancreatic cysts at many institutions. The inherent soft-tissue contrast of magnetic resonance cholangiopancreatography provides the vehicle for providing a specific diagnosis in many pancreatic cysts. Furthermore, an MRI-based characterization of pancreatic cysts allows for selection of those cysts that are more likely to benefit from endoscopic ultrasound and fine-needle aspiration for analysis of the fluid contents. Moreover, small asymptomatic incidental pancreatic cysts without concerning MRI features such as internal septae and/or nodularity may be safely followed with serial imaging. The lack of risk associated to repeated exposure to ionizing radiation and its ability to characterize pancreatic cysts are strong arguments for selecting MRI as the preferred imaging modality for following up these lesions. However, the recommendations for imaging follow-up continue to evolve, and several of the proposed guidelines are reviewed in this manuscript.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Serum carcinoembryonic antigen and carbohydrate antigen 19-9 for prediction of malignancy and invasiveness in intraductal papillary mucinous neoplasms of the pancreas: A meta-analysis

The clinical importance of intraductal papillary mucinous neoplasms (IPMN) of the pancreas has been increasing due to the large number of newly diagnosed cases. A meta-analysis was used to assess the accuracy of serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) for the identification of malignant and invasive IPMN. A literature search of PubMed and Web of Knowledge was conducted. Studies included in the analysis addressed the diagnostic accuracy of serum CEA and CA19-9 and pooled estimates of sensitivity, specificity, positive- and negative-likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR) and receiver operating characteristic curves were calculated using random-effects models. Predefined subgroup analysis was performed. Fifteen studies (published between 2001 and 2013) were analyzed, including a total of 1,629 patients. Pooled estimates of CEA in malignant and invasive IPNM prediction were: Pooled sensitivity, 18 and 18%; pooled specificity, 93 and 95%; PLR, 2.83 and 3.54; NLR, 0.89 and 0.89; and DOR, 3.35 and 3.6, respectively. Pooled estimates of CA19-9 in malignant and invasive IPMN prediction were: Pooled sensitivity, 40 and 52%; pooled specificity, 89 and 88%; PLR, 2.93 and 3.78; NLR, 0.74 and 0.6; and DOR, 4.34 and 6.33, respectively. In conclusion, serum CEA has low sensitivity and high specificity for malignant and invasive IPMN. Serum CA19-9 is a useful non-invasive preoperative tool for differentiating between invasive and benign IPMN and should be taken into account in the decision to perform surgery.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Extent of Surgery and Implications of Transection Margin Status after Resection of IPMNs

Appropriate surgical strategies for management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are a matter of debate. Preoperative and intraoperative evaluation of malignant potential of IPMN and of patient's comorbidities is of paramount importance to balance potential complications of surgery with tumors' risk of being or becoming malignant; the decision about the extent of pancreatic resection and the eventual total pancreatectomy needs to be determined on individual basis. The analysis of frozen-section margin of pancreas during operation is mandatory. The goal should be the complete resection of IPMN reaching negative margin, although there is still no agreed definition of “negative margin.” Of note, the presence of deepithelization is often wrongly interpreted as absence of neoplasia. Management of resection margin status and stratification of surveillance of the remnant pancreas, based on characteristics of primary tumour, are of crucial importance in the management of IPMNs in order to decrease the risk of tumor recurrence after resection. Although risk of local and distant recurrence for invasive IPMNs is increased even in case of total pancreatectomy, also local recurrence after complete resection of noninvasive IPMNs is not negligible. Therefore, a long-term/life-time follow-up monitoring is of paramount importance to detect eventual recurrences.

Endoscopic ultrasound in the diagnosis and treatment of pancreatic disease

Endoscopic ultrasound (EUS) is an important part of modern gastrointestinal endoscopy and now has an integral role in the diagnostic evaluation of pancreatic diseases. Furthermore, as EUS technology has advanced, it has increasingly become a therapeutic procedure, and the prospect of multiple applications of interventional EUS for the pancreas is truly on the near horizon. However, this review focuses on the established diagnostic and therapeutic roles of EUS that are used in current clinical practice. In particular, the diagnostic evaluation of acute pancreatitis, chronic pancreatitis, cystic pancreatic lesions and solid masses of the pancreas are discussed. The newer enhanced imaging modalities of elastography and contrast enhancement are evaluated in this context. The main therapeutic aspects of pancreatic EUS are then considered, namely celiac plexus block and celiac plexus neurolysis for pain control in chronic pancreatitis and pancreas cancer, and EUS-guided drainage of pancreatic fluid collections.

Diffusion-weighted magnetic resonance imaging for evaluating the histological degree of malignancy in patients with intraductal papillary mucinous neoplasm

BACKGROUND

The aim of this study was to evaluate the usefulness of high b-value diffusion-weighted magnetic resonance imaging (DWI) for evaluating the histological degree of malignancy in patients with intraductal papillary mucinous neoplasm (IPMN).

METHODS

A total of 35 patients (mean age 68 ± 10 years, 23 males) who had undergone DWI before surgery were included in this study. Of these 35 patients, 13 had IPMN with low- or intermediate-grade dysplasia, eight had IPMN with high-grade dysplasia, and 14 had IPMN with an associated invasive carcinoma. We evaluated the positive signal rate on DWI and the apparent diffusion coefficient (ADC) value of each pathology.

RESULTS

The positive signal rate on DWI of IPMN with low- or intermediate-grade dysplasia, of IPMN with high-grade dysplasia, and of IPMN with an associated invasive carcinoma were 0% (0/13), 38% (3/8), and 93% (13/14), respectively. The sensitivity, specificity, and accuracy for malignancy (IPMN with high-grade dysplasia or IPMN with an associated invasive carcinoma) using DWI were 73%, 100%, and 83%, respectively. The mean ADC value of malignancy was significantly lower than that of benignity (P = 0.002).

CONCLUSIONS

Diffusion-weighted magnetic resonance imaging, easily applicable in addition to conventional MRI, is considered an efficient modality for evaluating the histological degree of malignancy in patients with IPMN.

Not all mixed-type intraductal papillary mucinous neoplasms behave like main-duct lesions: implications of minimal involvement of the main pancreatic duct

BACKGROUND

The malignant potential of intraductal mucinous neoplasm of the pancreas (IPMN) is associated closely with main pancreatic duct (MPD) involvement. Because mixed-type IPMN is thought to have the same malignant potential as that of main-duct (MD)-IPMN, resection is recommended; however, the biological nature of mixed-type IPMN with only minimal involvement of MPD (min-mix-IPMN) may be different.

METHODS

A prospective database of 404 resected IPMNs was re-reviewed to subclassify mixed-type IPMNs. We defined min-mix-IPMN as absence of gross abnormalities (except for dilatation) of MPD and noncircumferential microscopic involvement of MPD limited to few sections.

RESULTS

We identified 46 min-mix-IPMNs, 163 IPMNs with extensive involvement of MPD (ex-mix-IPMN), 175 branch-duct (BD)-IPMNs, and 20 MD-IPMNs. The majority of min-mix-IPMNs were found incidentally and increased cyst size on surveillance was the leading operative indication. The median diameter of MPD was 2 mm in min-mix-IPMN versus 9 mm in ex-mix-IPMN (P < .0001), and cysts ≥10 mm were present in 62% of ex-mix-IPMNs versus 93% of min-mix-IPMNs (P < .0001). Most importantly, the vast majority of min-mix-IPMNs exhibited gastric-type epithelium, similar to BD-IPMNs, whereas intestinal-type epithelium was present in half of ex-mix-IPMNs, similar to MD-IPMNs. The prevalence of high-grade lesions was less in min-mix-IPMN than ex-mix-IPMN (P < .0001). These differences were reflected in better disease-specific outcomes of min-mix-IPMN compared with ex-mix-IPMN (P = .046).

CONCLUSION

Min-mix-IPMN often presents with no MPD dilation and is an incidental finding by microscopic examination. min-mix-IPMN shares the pathologic features and less aggressive biology with BD-IPMN. We propose that min-mix-IPMN be categorized differently than ex-mix-IPMN.

The role of cytopathology and cyst fluid analysis in the preoperative diagnosis and management of pancreatic cysts >3 cm

BACKGROUND

Pancreatic cyst size >3 cm is a worrisome rather than high-risk feature for malignancy based on the 2012 International Guidelines for the management of mucinous cysts. The value of cytology in preoperative evaluation and surgical triage is unclear.

METHODS

All pancreatic cysts >3 cm resected over a 7-year period were evaluated for clinical, radiologic, and pathologic information. Performance of cytology for the detection of malignancy and surgical triage compared with imaging was assessed.

RESULTS

There were 93 histologically confirmed cysts, 52 of which were mucinous and 41 of which were nonmucinous. Of these, 37% were malignant, including 16 nonmucinous malignancies and 18 mucinous cysts (12 with invasive carcinoma, 6 with high-grade dysplasia). Thirty-nine cysts (41% malignant, 59% benign) were not subject to endoscopic ultrasound-fine needle aspiration (EUS-FNA) prior to resection (average size, 6.0 cm). Fifty-four were evaluated by EUS-FNA, with 35 available for review (average size, 5.4 cm). Cytology/cyst fluid analysis had the highest specificity (88.9%) compared with imaging, whereas magnetic resonance imaging (MRI) showed the highest sensitivity (100%). MRI had the highest predictive value for mucinous (100%) versus nonmucinous cysts (100%). MRI and EUS were able to predict malignancy from the presence of high-risk imaging features in all cases. Some benign cases also showed high-risk imaging features on MRI (28.6%), computed tomography (32.3%), and EUS (45.8%). Cytology correctly classified 5 of 6 benign cysts with high-risk imaging as benign.

CONCLUSIONS

Preoperative evaluation of pancreatic cysts >3 cm is warranted, as many are nonmucinous cysts and not high-grade. Cytology is more specific than imaging for the detection of malignancy in cysts >3 cm.

Utility of the sendai consensus guidelines for branch-duct intraductal papillary mucinous neoplasms: a systematic review

INTRODUCTION

The Sendai Consensus Guidelines (SCG) was formulated in 2006 to guide the management of intraductal papillary mucinous neoplasms (IPMN). The main area of controversy is the criteria for selection of branch duct (BD)-IPMN for resection. Although these guidelines have gained widespread acceptance, there is limited data to date supporting its use. This systematic review is performed to evaluate the utility of the Sendai Consensus Guidelines (SCG) for BD-IPMN.

METHODS

Studies evaluating the clinical utility of the SCG in surgically resected neoplasms were identified. The SCG were retrospectively applied to all resected neoplasms in these studies. BD-IPMNs which met the criteria for resection were termed SCG+ve and those for surveillance were termed SCG-ve.

RESULTS

Twelve studies were included, of which, 9 were suitable for pooled analysis. There were 690 surgically resected BD-IPMNs, of which, 24% were malignant. Five hundred one BD-IPMNs were classified as SCG+ve and 189 were SCG-ve. The positive predictive value (PPV) of SCG+ve neoplasms ranged from 11 to 52% and the NPV of SCG-ve neoplasms ranged from 90 to 100%. Overall, there were 150/501 (29.9%) of malignant BD-IPMNs in the SCG+ve group and 171/189 (90%) of benign BD-IPMNs in the SCG-ve group. Of the 18 reported malignant (11 invasive) BD-IPMNs in the SCG-ve group, 17 (including all 11 invasive) were from a single study. When the results from this single study were excluded, 170/171 (99%) of SCG-ve BD-IPMNs were benign.

CONCLUSION

The results of this review confirm the limitations of the SCG for BD-IPMN. The PPV of the SCG in predicting a malignant BD-IPMN was low and some malignant lesions may be missed based on these guidelines.

Endoscopic ultrasound in the diagnosis of pancreatic intraductal papillary mucinous neoplasms

Pancreatic cystic lesions are increasingly recognised due to the widespread use of different imaging modalities. Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas represent a common, but also heterogeneous group of cystic tumors with a significant malignant potential. These neoplasms must be differentiated from other cystic tumors and properly classified into their different types, main-duct IPMNs vs branch-duct IPMNs. These types have a different malignant potential and therefore, different treatment strategies need to be implemented. Endoscopic ultrasound (EUS) offers the highest resolution of the pancreas and can aid in the differential diagnosis, classification and differentiation between benign and malignant tumors. The addition of EUS fine-needle aspiration can supply further information by obtaining fluid for cytology, measurement of tumor markers and perhaps DNA analysis. Novel techniques, such as the use of contrast and sophisticated equipment, like intraductal probes can provide information regarding malignant features and extent of these neoplasms. Thus, EUS is a valuable tool in the diagnosis and appropriate management of these tumors.

Uncinate duct dilation in intraductal papillary mucinous neoplasms of the pancreas: a radiographic finding with potentially increased malignant potential

BACKGROUND

Risk of high-grade dysplasia and invasive carcinoma in intraductal papillary mucinous neoplasms (IPMN) of the pancreas is increased in main duct compared to branch duct lesions. We hypothesized that isolated uncinate duct dilation may also be a radiographic indicator of high-risk disease, as the primary drainage of this portion of the gland originates from a distinct embryologic precursor.

METHODS

All patients with available preoperative imaging who underwent resection for IPMN between 1994 and 2010 were included (n = 184). Imaging studies were reviewed by an experienced radiologist who was blinded to the pathologic results, and studies were categorized as main duct, branch duct, or combined-duct. The presence of uncinate duct dilation was assessed as a risk factor for tumors which proved to have high-grade dysplasia (HGD) or invasive carcinoma (IC) on pathologic assessment.

RESULTS

IPMN with HGD or IC were identified in 82 of 184 cases (45%). Without considering uncinate duct dilation, IPMN with HGD or IC were present in 84% of patients with main duct IPMN (n = 31/37), 58% with combined-duct IPMN (n = 23/40), and 26% with branch \duct IPMN (n = 28/107). Dilation of the uncinate duct was observed in 47 patients, with or without main duct dilation, and 30 of these (64%) contained HGD or IC on pathology. Isolated uncinate duct dilation without main duct dilation was observed in 17 patients, and 11 (65%) had HGD. On multivariate analysis of IPMN without associated main duct dilation, uncinate duct dilation was independently associated with IPMN with HGD or IC (p = 0.002).

CONCLUSION

Uncinate duct dilation on preoperative radiologic imaging appears to be an additional risk factor for IPMN-associated high-grade dysplasia or adenocarcinoma.

Cyst infection of intraductal papillary mucinous neoplasms of the pancreas: management of a rare complication: report of 2 cases

The purpose of this study was to describe the cyst infection of intraductal papillary mucinous neoplasm in 2 patients. The patients were 62- and 74-year-old men. The initial symptom was acute febrile abdominal pain. Laboratory tests revealed severe infection (C-reactive protein concentrations were 23.3 µg/mL in patient 1 and 22.3 µg/mL in patient 2) and multilocular cystic masses (the diameters were 70 mm in patient 1 and 50 mm in patient 2) at the pancreatic head that involved peripancreatic vessels were demonstrated by computed tomography. Laboratory and radiographic findings were markedly improved by endoscopic transpapillary drainage. The enteric bacteria were detected in the drainage specimens. Curative resection was achieved, and histological findings indicated a carcinoma in situ in patient 1 and an invasive carcinoma in patient 2. Neither hyperamylasemia nor histological fat necrosis, frequently observed in acute pancreatitis, was evident. Both patients were free from recurrence after surgery (17 months in patient 1, and 18 months in patient 2). Cyst infection is an unknown complication of intraductal papillary mucinous neoplasm. Transpapillary drainage is highly recommended as an initial intervention. It is difficult to distinguish between cyst infection and unresectable invasive carcinoma with imaging modalities; however, surgical intervention after drainage may contribute to long-term survival.

Can long-term follow-up strategies be determined using a nomogram-based prediction model of malignancy among intraductal papillary mucinous neoplasms of the pancreas?

OBJECTIVES

This study investigated whether a risk assessment nomogram can predict the malignant potential of intraductal papillary mucinous neoplasms (IPMNs) and provide valuable information for the follow-up and counseling strategies of such patients.

METHODS

We studied 126 of 589 patients with IPMN who were followed up for at least 36 months with annual endoscopic ultrasonography. We analyzed scores derived from our nomogram, incorporating the parameters of sex, lesion type, mural nodule height, and pancreatic juice cytology determined at the initial IPMN evaluation.

RESULTS

The rate of malignant IPMNs was 5.5% (7/126). The initial average nomogram score was 19.8 (range, 0-55), and the final follow-up average was 23.8 (range, 0-109). When a cutoff score was set at 35 points, the sensitivity, specificity, and accuracy of the nomogram to assess malignancy risk were 87.5%, 96.6%, and 96%, respectively. The area under the receiver operating characteristic curve of malignant IPMN prediction during follow-up was 0.865.

CONCLUSIONS

The ability of the nomogram to predict malignancy in patients with IPMN was validated. Our findings can suggest that a follow-up for patients at high and low risk for cancer progression could be scheduled every 3 to 6 and 12 months, respectively.

Prevalence of malignancy in patients with pure main duct intraductal papillary mucinous neoplasms

BACKGROUND

Risk of malignancy in main duct intraductal papillary mucinous neoplasm (MD-IPMN) ranges from 36% to 100% in the literature. Although surgical resection is recommended for all MD-IPMNs, the risk of malignancy based on main pancreatic duct (MPD) size alone remains unclear.

OBJECTIVE

To assess the prevalence of malignancy in symptomatic and asymptomatic patients with pure MD-IPMN based on MPD size.

DESIGN

Single-center retrospective study of prospectively collected data.

SETTINGS

Tertiary referral center.

PATIENTS AND INTERVENTIONS

Fifty-two patients with pure low-risk MD-IPMN. Clinical, endoscopic, radiographic, and pathologic data were reviewed.

MAIN OUTCOME MEASUREMENTS

Prevalence of malignancy in patients with pure MD-IPMN based on histopathology of resected lesions.

RESULTS

Sixteen asymptomatic patients had pure MD-IPMN on surgical pathology, 4 (25%) with malignant disease, compared with 25 of 36 symptomatic patients (69%) with pure MD-IPMN. Logistic regression identified symptoms and MPD size as predictors of malignancy. Receiver operating characteristic curve analysis demonstrated that MPD size (optimal cutoff of 8 mm) produced the greatest area under the curve to discriminate between benign and malignant MD-IPMN (.83; 95% CI, .72-.94). MPD size greater than 8 mm has a relative risk of 2.8 for malignancy (95% CI, 1.6-4.9).

LIMITATIONS

Retrospective, single-center study at a tertiary referral hospital. Study population included only patients who underwent surgical resection.

CONCLUSION

Asymptomatic MD-IPMN patients with a duct size of no more than 8 mm have a lower prevalence of malignancy and may represent a distinct group of patients with less aggressive biologic behavior. Further studies are needed to confirm our observations.

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.

Nonoperative management of main pancreatic duct-involved intraductal papillary mucinous neoplasm might be indicated in select patients

BACKGROUND

Although the natural history of intraductal papillary mucinous neoplasm (IPMN) remains unclear, large surgical series have reported malignancy in 40% to 90% of main pancreatic duct (MPD)-involved IPMN. Accordingly, the 2012 International Consensus Guidelines recommend surgical resection in patients with suspected MPD involvement. We hypothesized that nonoperative management of select patients with suspected MPD-involved IPMN might be indicated.

STUDY DESIGN

From 1992 to 2012, 362 patients underwent surgical resection for pathologically confirmed IPMN at a single academic center. A retrospective review of prospectively collected data was performed. Main pancreatic duct involvement was suspected with an MPD diameter ≥5 mm on preoperative imaging. A multivariate analysis was conducted to assess predictors of malignancy.

RESULTS

Of 362 patients, 334 had complete data for analysis. Main pancreatic duct involvement was suspected preoperatively in 171 patients. Final pathology revealed 20% high-grade dysplastic and 27% invasive IPMN (47% malignant). Preoperative cytopathology and serum carbohydrate antigen 19-9 independently predicted malignancy (p = 0.003 and p = 0.002, respectively) and invasiveness (p < 0.0001 and p = 0.001, respectively). Patients with both negative preoperative cytopathology and normal serum carbohydrate antigen 19-9 (ie, double negatives) had a lower rate of malignancy and invasiveness (28% and 8% vs 58% and 38%; p < 0.0001). The MPD diameter did not predict malignancy or invasiveness (p = 0.36 and p = 0.46, respectively).

CONCLUSIONS

Patients with suspected MPD-involved IPMN have a highly variable rate of malignancy. Despite recent International Consensus Guidelines recommendations, these data suggest that MPD diameter is not an optimal gauge of malignant risk. Nonoperative management of suspected MPD-involved IPMN in select patients, particularly double negatives, might be indicated. Depending on age and comorbidity, operative risk might outweigh the risk of malignant progression in these patients.

Multidisciplinary diagnostic and therapeutic approaches to pancreatic cystic lesions

Pancreatic cystic lesions are commonly encountered today with the routine use of cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). The majority of patients discovered to have a pancreatic cyst are completely asymptomatic; yet the presence of such a finding instills fear in the minds of both patient and physician, as the concern for malignant transformation to pancreatic cancer is great despite the relatively low overall likelihood of cyst progression. Not all cysts in the pancreas represent pancreatic cystic neoplasms (PCNs), and not all PCNs have significant malignant potential. Mucinous PCNs are the most concerning, as these lesions have the greatest potential for cancerous transformation to adenocarcinoma. Within the group of mucinous PCNs, intraductal papillary mucinous neoplasms (IPMNs) involving the main pancreatic duct are the most worrisome, and surgical resection should be pursued if the patient has appropriate operative risks. IPMN lesions involving the branch ducts, and mucinous cystadenomas, have a lower likelihood for malignancy, and they may be closely followed for the development of any worrisome or high-risk features. Surveillance of known PCNs is performed with a combination of CT, MRI and endoscopic ultrasound (EUS). EUS-guided fine-needle aspiration (EUS-FNA) may be used to assess cyst fluid cytology, and also to detect cyst fluid amylase level, carcinoembryonic antigen level, and DNA molecular analysis in certain cases. The presence or absence of specific cyst morphological features, as well as the cyst fluid analysis, is what enables the physician to guide the patient towards continued surveillance, versus the pursuit of surgical resection.

Blood group type antigens in pancreatic intraductal papillary mucinous neoplasms

BACKGROUND

There are few data on blood group (BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms (IPMNs).

METHODS

BG type and tumor BG-antigen (glycoprotein) expression (studied by immunohistochemistry on tissue microarrays) were analyzed with regard to characteristics of 101 surgically resected pancreatic IPMNs.

RESULTS

Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type A was observed more frequently in women than in men. Chronic pancreatitis was more frequently seen in patients with BG type B or AB. Aberrant tumor expression (with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneoplasm BG-antigen expression was not related to dysplasia grade or invasion.

CONCLUSION

The results of the study suggest that in pancreatic IPMN, non-O BG type predicted invasive carcinoma, whereas for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion.