Intraductal papillary mucinous neoplasms and other pancreatic cystic lesions

Pancreatic cystic neoplasms are being increasingly recognized, even in the absence of symptoms, in large part, due to markedly improved imaging modalities such as magnetic resonance imaging (MRI)/magnetic resonance cholangio pancreatography (MRCP) and computer tomography (CT) scanning. During the past 2 decades, better imaging of these cystic lesions has resulted in definition of different types, including pancreatic intraductal papillary mucinous neoplasms (IPMN). While IPMN represent only a distinct minority of all pancreatic cancers, they appear to be a relatively frequent neoplastic form of pancreatic cystic neoplasm. Moreover, IPMN have a much better outcome and prognosis compared to pancreatic ductal adenocarcinomas. Therefore, recognition of this entity is exceedingly important for the clinician involved in diagnosis and further evaluation of a potentially curable form of pancreatic cancer.

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 branchduct 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.

Endosonographic diagnosis of advanced neoplasia in intraductal papillary mucinous neoplasms

Pancreatic cancer has a high mortality rate with minimal proven interventions.Intraductal Papillary Mucinous Neoplasms(IPMNs) are known precursor lesions for pancreatic cancer. Identification of pancreatic cysts has improved from advances in abdominal imaging. Despite multiple revisions of the international consensus recommendations and various guidelines by other major societies,successful risk stratification of the malignant potential of mucinous pancreatic cysts remains challenging. Specifically, detection and accurate classification of advanced neoplasia(high-grade dysplasia and/or adenocarcinoma) in IPMNs is suboptimal with current diagnostic strategies. Development of interventional techniques utilizing endoscopic ultrasound include-through-the-needle microforceps biopsy, next-generation or whole genome molecular analysis of cyst fluid, and needle-based confocal laser endomicroscopy. These techniques suffer from a series of limitations in technical success, diagnostic yield, and clinical feasibility, but a combination approach may offer a solution that optimizes their cyst evaluation and risk stratification. Assessment and comparison of these techniques is restricted by lack of adequate surgical specimens for testing of diagnostic accuracy, resulting in a possible sample bias. Additional large-scale multicenter studies are needed to accumulate evidence for the utility and feasibility of their translation into clinical practice. Great strides have been made in pancreatic cyst evaluation, but further research is required to improve diagnostic accuracy and clinical management of IPMNs.

Higher volume growth rate is associated with development of worrisome features in patients with branch duct-intraductal papillary mucinous neoplasms

BACKGROUND Branch duct-intraductal papillary mucinous neoplasms(BD-IPMNs)are the most common pancreatic cystic tumours and have a low risk of malignant transformation.Current guidelines only evaluate cyst diameter as an important risk factor but it is not always easy to measure,especially when comparing different methods.On the other side,cyst volume is a new parameter with low interobserver variability and is highly reproducible over time.AIM To assess both diameter and volume growth rate of BD-IPMNs and evaluate their correlation with the development of malignant characteristics.METHODS Computed tomography scans and magnetic resonance imaging exams were retrospectively reviewed.The diameter was measured on three planes,while the volume was calculated by segmentation:The volume of the entire cyst was determined by manually drawing a region of interest along the edge of the neoplasm on each consecutive slice covering the whole lesion;therefore,a threedimensional volume of interest was finally obtained with the calculated value expressed in cm^(3).Changes in size over time were measured.The development of worrisome features was evaluated.RESULTS We evaluated exams of 98 patients across a 40.5-mo median follow-up time.Ten patients developed worrisome features.Cysts at baseline were significantly larger in patients who developed worrisome features(diameters P=0.0035,P=0.00652,P=0.00424;volume P=0.00222).Volume growth rate was significantly higher in patients who developed worrisome features(1.12 cm^(3)/year vs 0 cm^(3)/year,P=0.0001);diameter growth rate was higher as well,but the difference did not always reach statistical significance.Volume but not diameter growth rate in the first year of follow-up was higher in patients who developed worrisome features(0.46 cm^(3)/year vs 0 cm^(3)/year,P=0.00634).CONCLUSION The measurement of baseline volume and its variation over time is a reliable tool for the follow-up of BD-IPMNs.Volume measurement could be a better tool than diameter measurement to predict the development of worrisome features.

Multiphase computed tomography radiomics of pancreatic intraductal papillary mucinous neoplasms to predict malignancy

BACKGROUND Intraductal papillary mucinous neoplasms(IPMNs)are non-invasive pancreatic precursor lesions that can potentially develop into invasive pancreatic ductal adenocarcinoma.Currently,the International Consensus Guidelines(ICG)for IPMNs provides the basis for evaluating suspected IPMNs on computed tomography(CT)imaging.Despite using the ICG,it remains challenging to accurately predict whether IPMNs harbor high grade or invasive disease which would warrant surgical resection.A supplementary quantitative radiological tool,radiomics,may improve diagnostic accuracy of radiological evaluation of IPMNs.We hypothesized that using CT whole lesion radiomics features in conjunction with the ICG could improve the diagnostic accuracy of predicting IPMN histology.AIM To evaluate whole lesion CT radiomic analysis of IPMNs for predicting malignant histology compared to International Consensus Guidelines.METHODS Fifty-one subjects who had pancreatic surgical resection at our institution with histology demonstrating IPMN and available preoperative CT imaging were included in this retrospective cohort.Whole lesion semi-automated segmentation was performed on each preoperative CT using Healthmyne software(Healthmyne,Madison,WI).Thirty-nine relevant radiomic features were extracted from each lesion on each available contrast phase.Univariate analysis of the 39 radiomics features was performed for each contrast phase and values were compared between malignant and benign IPMN groups using logistic regression.Conventional quantitative and qualitative CT measurements were also compared between groups,viaχ2(categorical)and Mann Whitney U(continuous)variables.RESULTS Twenty-nine subjects(15 males,age 71±9 years)with high grade or invasive tumor histology comprised the"malignant"cohort,while 22 subjects(11 males,age 70±7 years)with low grade tumor histology were included in the"benign"cohort.Radiomic analysis showed 18/39 precontrast,19/39 arterial phase,and 21/39 venous phase features differentiated malignant from benign IPMNs(P<0.05).Multivariate analysis including only ICG criteria yielded two significant variables:thickened and enhancing cyst wall and enhancing mural nodule<5 mm with an AUC(95%CI)of 0.817(0.709-0.926).Multivariable post contrast radiomics achieved an AUC(95%CI)of 0.87(0.767-0.974)for a model including arterial phase radiomics features and 0.834(0.716-0.953)for a model including venous phase radiomics features.Combined multivariable model including conventional variables and arterial phase radiomics features achieved an AUC(95%CI)of 0.93(0.85-1.0)with a 5-fold cross validation AUC of 0.90.CONCLUSION Multi-phase CT radiomics evaluation could play a role in improving predictive capability in diagnosing malignancy in IPMNs.Future larger studies may help determine the clinical significance of our findings.

Expression of the tumor suppressor gene maspin and its significance in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND: Maspin is a member of the serpin family of protease inhibitors and is thought to inhibit carcinoma invasion, metastasis, and angiogenesis and induce apoptosis. We examined maspin expression immunohistochemically and assessed its significance in intraductal papillary mucinous neoplasm (IPMN) of the pancreas. METHODS: We examined 39 surgically resected specimens of IPMN that included 17 adenomas (IPMAs), 5 borderline tumors (IPMBs), 4 non-invasive carcinomas (non-invasive IPMCs), and 13 invasive carcinomas (invasive IPMCs). Immunostaining was performed according to the EnVision ChemMate method. The degree of maspin expression was scored and assessed according to the percentage and staining intensity of positive cells. RESULTS: Maspin expression was minimal in normal pancreatic duct epithelium, whereas in IPMNs, maspin was expressed in neoplasms of all stages. Maspin expression increased with increasing grade from IPMAs, IPMBs, to non-invasive IPMCs but decreased significantly in invasive IPMCs. No specific association between maspin expression and mucin type was found. Analysis of maspin expression with respect to clinicopathologic factors in cases of invasive IPMC revealed a greater extent of invasion in cases of low maspin expression and significantly fewer apoptotic cells in the tumor.CONCLUSIONS: Maspin was expressed at high levels in IPMNs at various stages from adenoma to invasive carcinoma, and our results suggest that maspin may be involved in the occurrence and progression of IPMN. In addition, our data suggest that the apoptosis-inducing action of maspin suppresses invasion and progression of IPMN.

Pancreatic intraductal papillary mucinous neoplasms:Current diagnosis and management

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

Imaging features of intraductal papillary mucinous neoplasms of the pancreas in multi-detector row computed tomography

AIM:To retrospectively evaluate the imaging features of pancreatic intraductal papillary mucinous neoplasms (IPMNs) in multi-detector row computed tomography (MDCT).METHODS: A total of 20 patients with pathologically-confirmed intraductal papillary mucinous neoplasms (IPMNs) were included in this study. Axial MDCT images combined with CT angiography (CTA) and multiplanar volume reformations (MPVR) or curved reformations (CR) were preoperatively acquired. Two radiologists (Tan L and Wang DB) reviewed all the images in consensus using an interactive picture archiving and communication system. The disputes in readings were resolved through consultation with a third experienced radiologist (Chen KM). Finally, the findings and diagnoses were compared with the pathologic results.RESULTS: The pathological study revealed 12 malignant IPMNs and eight benign IPMNs. The diameters of the cystic lesions and main pancreatic ducts (MPDs) were significantly larger in malignant IPMNs compared with those of the benign IPMNs (P<0.05). The combined-type IPMNs had a higher rate of malignancy than the other two types of IPMNs (P<0.05). Tumors with mural nodules and thick septa had a significantly higher incidence of malignancy than tumors without these features (P<0.05). Communication of side-branch IPMNs with the MPD was present in nine cases at pathologic examination. Seven of them were identified from CTA and MPVR or CR images. From comparison with the pathological diagnosis, the sensitivity, specificity, and accuracy of MDCT in characterizing the malignancy of IPMN of the pancreas were determined to be 100%, 87.5% and 95%, respectively.CONCLUSION: MDCT with CTA and MPVR or CR techniques can elucidate the imaging features of IPMNs and help predict the malignancy of these tumors.

molecular pathology of intraductal papillary mucinous neoplasms of the pancreas

Since the first description of intraductal papillary mucinous neoplasms(IPMNs)of the pancreas in the eighties,their identification has dramatically increased in the last decades,hand to hand with the improvements in diagnostic imaging and sampling techniques for the study of pancreatic diseases.However,the heterogeneity of IPMNs and their malignant potential make difficult the management of these lesions.The objective of this review is to identify the molecular characteristics of IPMNs in order to recognize potential markers for the discrimination of more aggressive IPMNs requiring surgical resection from benign IPMNs that could be observed.We briefly summarize recent research findings on the genetics and epigenetics of intraductal papillary mucinous neoplasms,identifying some genes,molecular mechanisms and cellular signaling pathways correlated to the pathogenesis of IPMNs and their progression to malignancy.The knowledge of molecular biology of IPMNs has impressively developed over the last few years.A great amount of genes functioning as oncogenes or tumor suppressor genes have been identified,in pancreatic juice or in blood or in the samples from the pancreatic resections,but further researches are required to use these informations for clinical intent,in order to better define the natural history of these diseases and to improve their management.

Nomograms predicting long-term survival in patients with invasive intraductal papillary mucinous neoplasms of the pancreas: A population-based study

BACKGROUND There are few effective tools to predict survival in patients with invasive intraductal papillary mucinous neoplasms of the pancreas.AIM To develop comprehensive nomograms to individually estimate the survival outcome of patients with invasive intraductal papillary mucinous neoplasms of the pancreas.METHODS Data of 1219 patients with invasive intraductal papillary mucinous neoplasms after resection were extracted from the Surveillance,Epidemiology,and End Results database,and randomly divided into the training(n=853)and the validation(n=366)cohorts.Based on the Cox regression model,nomograms were constructed to predict overall survival and cancer-specific survival for an individual patient.The performance of the nomograms was measured according to discrimination,calibration,and clinical utility.Moreover,we compared the predictive accuracy of the nomograms with that of the traditional staging system.RESULTS In the training cohort,age,marital status,histological type,T stage,N stage,M stage,and chemotherapy were selected to construct nomograms.Compared with the American Joint Committee on Cancer 7th staging system,the nomograms were generally more discriminative.The nomograms passed the calibration steps by showing high consistency between actual probability and nomogram prediction.Categorial net classification improvements and integrated discrimination improvements suggested that the predictive accuracy of the nomograms exceeded that of the American Joint Committee on Cancer staging system.With respect to decision curve analyses,the nomograms exhibited more preferable net benefit gains than the staging system across a wide range of threshold probabilities.CONCLUSION The nomograms show improved predictive accuracy,discrimination capability,and clinical utility,which can be used as reliable tools for risk classification and treatment recommendations.

Simultaneous liver mucinous cystic and intraductal papillary mucinous neoplasms of the bile duct:A case report

Cystic hepatic neoplasms are rare tumors,and are classified into two separate entities:mucinous cystic neoplasms(MCNs)and intraductal papillary mucinous neoplasms of the bile duct(IPMN-B).We report the case of a 56-year-old woman who presented with abdominal pain and jaundice due to the presence of a large hepatic multilocular cystic tumor associated with an intraductal tumor.Partial hepatectomy with resection of extrahepatic bile ducts demonstrated an intrahepatic MCN and an intraductal IPMN-B.This is the first report of the simultaneous occurrence of these two histologically distinct entities in the liver.

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.

Evolution of incidental branch-duct intraductal papillary mucinous neoplasms of the pancreas: A study with magnetic resonance imaging cholangiopancreatography

AIM To investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms(bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography(MRCP) follow-up.METHODS We retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs(mean 4.4) to follow-up incidental, presumed bdIPMN without signs of malignancy, found or confirmedat a baseline MRCP examination. Median follow-up time was 48.5 mo(range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes:(1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and(2) alert findings, defined as worrisome features and/or high risk stigmata(e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.RESULTS We found a total of 343 cysts(per-patient mean 5.1) with average size of 8.5 mm(range 5-25 mm). Imaging evolution was observed in 32/72 patients(44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts(13.7%). There was a main trend towards small(< 10 mm) increase and/or decrease of cysts size at a median time of 22.5 mo. Alert findings developed in 6/72 patients(8.3%; 95%CI: 3.4-17.9) over a wide interval of time(13-63 mo). No malignancy was found on endoscopic ultrasound with fine-needle aspiration(5/6 cases) or surgery(1/6 cases). No clinical or initial MRCP features were significantly associated with changes in bd-IPMN appearance(P > 0.01).CONCLUSION Changes in MRCP appearance of incidental bd-IPNM were frequent over the follow-up(44.4%), with relatively rare(8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging followup should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.

Synchronous manifestation of colorectal cancer and intraductal papillary mucinous neoplasms

High rates of extrapancreatic malignancies,in particular colorectal cancer(CRC),have been detected in patients with intraductal papillary mucinous neoplasm(IPMN).So far,there is no distinct explanation in the literature for the development of secondary or synchronous malignancies in patients with IPMN.In the past few years,some data related to common genetic alterations in IPMN and other affiliated cancers have been published.This review elucidated the association between IPMN and CRC,shedding light on the most relevant genetic alterations that may explain the possible relationship between these entities.In keeping with our findings,we suggested that once the diagnosis of IPMN is made,special consideration of CRC should be undertaken.Presently,there are no specific guidelines regarding colorectal screening programs for patients with IPMN.We recommend that patients with IPMNs are at high-risk for CRC,and a more rigorous colorectal surveillance program should be implemented.

Favorable response after radiation therapy for intraductal papillary mucinous neoplasms manifesting as acute recurrent pancreatitis:A case report

BACKGROUND There has been an increasing number of elderly patients with intraductal papillary mucinous neoplasm(IPMN),who are surgically intolerant and require less invasive treatment options,which are limited.In the present study,we report a case of IPMN presenting with acute recurrent pancreatitis(ARP),in which radiation therapy effectively prevented further attacks of ARP and reduced tumor volume.CASE SUMMARY An 83-year-old man was referred to our hospital with an asymptomatic incidental pancreatic cyst.Endoscopic ultrasound imaging and magnetic resonance cholangiopancreatography revealed a multiloculated tumor in the head of the pancreas,with dilated pancreatic ducts and mural nodules.The patient was diagnosed with mixed-type IPMN,and five years later,he developed ARP.Several endoscopic pancreatic ductal balloon dilatations failed to prevent further ARP attacks.Surgery was considered clinically inappropriate because of his old age and comorbidities.He was referred to our department for radiation therapy targeted at those lesions causing intraductal hypertension and radiation was administered at a dose of 50 Gy.An magnetic resonance imaging scan taken ten weeks after treatment revealed a decrease in tumor size and improvement of pancreatic duct dilatation.Fourteen months later,he remains symptom-free from ARP.CONCLUSION This case highlights the important role of radiation therapy in mitigating the signs and symptoms of ARP in patients with inoperable IPMN.

Predictive factors associated with malignancy of intraductal papillary mucinous pancreatic neoplasms

AIM:To identify preoperative predictive factors associated with malignancy of intraductal papillary mucinous neoplasms(IPMNs) of the pancreas.METHODS:Between April 1995 and April 2010,129 patients underwent surgical resection for IPMNs at our institute and had confirmed pathologic diagnoses.The medical records were retrospectively reviewed and immunohistochemical staining for mucin(MUC) in pancreatic tissues was performed.RESULTS:Univariate analysis showed that the following five variables were closely associated with malignant IPMNs preoperatively:absence of extrapancreatic malignancy;symptoms;tumor size > 4 cm;main pancreaticduct(MPD) size > 7 mm;and lymph node enlargement on preoperative computed tomography(CT).Multivariate analysis revealed that the following two factors were significantly associated with malignant IPMNs preoperatively:MPD size > 7 mm [odds ratio(OR) = 2.50];and lymph node enlargement on preoperative CT(OR = 3.57).No significant differences in the expression of MUC1,MUC2 and MUC5AC were observed between benign and malignant IPMNs.CONCLUSION:MPD size > 7 mm and preoperative lymph node enlargement on CT are useful predictive factors associated with malignancy of IPMNs.

The clinicopathologic features of intraductal papillary mucinous neoplasms of the pancreas

Since first described in 1982,intraductal papillary mucinous neoplasm(IPMN)has been the preferred term to describe the proliferation of the pancreatic ductal epithelium.It is totally different from pancreatic carcinoma in epi demiology,histology,pathology and prognosis.According to the site of involvement,IPMNs are classified into three categories,i.e.main duct type,branch duct type,and combined type.Most branch duct IPMNs are benign,whereas the other two types are often malignant.A large branch duct IPMN and marked dilation of the main pancreatic duct indicate the presence of adenoma at least.The additional existence of large mural nodules increases the possibility of malignancy in all types.The prognosis is more favorable after complete resection of benign and non-invasive malignant IPMNs.Malignant IPMNs that become more aggressive after parenchymal invasion necessitate adequate lymph node dissection.On the other hand,asymptomatic branch duct IPMNs without mural nodules can be observed without the need for resection for a considerable period of time.Our review addresses available data,current understanding,controversy,and future directions about IPMNs.

Lessons learned from hepatocellular carcinoma may cause a paradigm shift in intraductal papillary mucinous neoplasms:a narrative review and discussion of conceptual similarities in tumor progression and recurrence

Although the natural history of recurrence/progression in patients with intraductal papillary mucinous neoplasms (IPMN) of the pancreas has not been studied thoroughly, the three principal mechanisms have been identified: (a) presence of residual disease at the transection margin, (b) presence of intraductal/intraparenchymal metastases and (c) development of new primary lesions. Mechanisms (a) and (b) result in metastatic lesions that are genetically related to the primary, while new primary lesions (mechanism c) are genetically distinct. Interestingly, recurrence/progression in IPMN displays conceptual parallels with the well-established paradigm of disease recurrence in patients with hepatocellular carcinoma (HCC). Specifically, patients with HCC may also develop recurrent tumors due to microscopic residual disease/intrahepatic metastasis which are genetically similar to the primary while the development of genetically unrelated, de novo HCC after curative-intent resection is also common. The latter has been attributed to the presence of a widespread genetic abnormality ( "field defect" ) in the liver (ie, cirrhosis). Given the conceptual similarities between IPMN and HCC, a pancreatic "field defect" may also be hypothesized to exist. This review does not suggest that HCC and IPMN have identical pathogeneses, but rather that they have conceptual similarities in tumor recurrence/progression;thus, lessons learned from HCC could be applied to IPMN research and subsequent management. Conceptual similarities in tumor progression and recurrence may also be observed between IPMN and other malignancies. However, HCC was selected because it is well studied and can serve as a paradigm.

Clinical implications of the molecular characterization of intraductal papillary mucinous neoplasms of the pancreas

Intraductal papillary mucinous neoplasm(IPMN)is a pre-malignant,mucin-producing epithelial lesion arising from pancreatic ducts.Observational reports define IPMN behavior as ranging from indolent,asymptomatic lesions to dysplasia that sometimes degenerate into pancreatic adenocarcinoma.The goal of IPMN management is risk-reducing surgery for high-risk cysts and observation of the remainder.Discriminating high-from low-risk IPMN disease still relies on imaging and clinical cyst characteristics.Here,we review the accepted classification of IPMN including the most common histological subtypes,their clinical features,and currently-accepted high-risk phenotypes.We then deeply examine the known molecular landscape of IPMN,which has largely been derived from post-resection analysis.This includes those gene variants unique to IPMN,chiefly GNAS and RNF43,but also examines the overlap between IPMN and conventional pancreatic adenocarcinoma.Utilizing molecular markers in the clinical setting relies on endoscopically-obtained cyst fluid and presumes that it accurately represents the molecular characteristics of the cystic epithelium.We synthesize existing data on mutational analysis from IPMN cyst fluid and consider the benefits and proper role of current commercially-available cyst fluid molecular analysis kits.We conclude that carefully interpreted molecular analysis of resected IPMN tissue reveals insights into its biology and natural history while cyst fluid analysis offers prognostication and data to guide treatment decisions.However,knowledge gaps remain,especially in characterizing IPMN molecular heterogeneity,time to progression,and correlating cyst fluid genotype data with surveillance strategies.As such,substantial additional research is required before the promise of true molecular guidance of IPMN management can be realized.

Malignancies associated with intraductal papillary mucinous neoplasm of the pancreas

AIM： As intraductal papillary mucinous neoplasm （IPMN） has a favorable prognosis, associated malignancies have potential significance in these patients. We examined the incidence and characteristics of pre-existing, coexisting and subsequent malignancies in patients with IPMN. METHODS： Seventy-nine cases of IPMN were diagnosed by detection of mucous in the pancreatic duct during endoscopic retrograde pancreatography. Histological diagnosis was confirmed in 30 cases （adenoma （n = 19） and adenocarcinoma （n = 11）. Other primary malignancies associated with IPMN, occurring in the prediagnostic or postdiagnostic period, were investigated. Postdiagnostic follow-up period was 3.3±0.5 years （range, 0.2-20 years）. RESULTS： Other 40 malignancies occurred in 28 patients （35%）. They were found before （n = 15）, at （n = 19） and after （n = 6） the diagnosis of IPMT. Major associated malignancies were gastric cancer （n = 12）, colonic cancer （n = 7）, esophageal cancer （n = 4）, pulmonary cancer （n = 4）, and independent pancreatic cancer （n = 3）. Pancreatic cancer was synchronous with IPMN in two patients and metachronous in one （3 years after diagnosis of IPMN）. Thirty-one lesions were treated surgically or endoscopically. Fourteen patients died of associated cancers. Development of other malignancies was related to age （71.9±8.2 v566.8±9.3, P〈0.05）, but not to gender or site of the tumor. CONCLUSION： IPMN is associated with a high incidence of other malignancies, particularly gastric and colonic cancers. Common genetic mechanisms between IPMN and other associated malignancies might be present. Clinicians should pay attention to the possibility of associated malignancies in preoperative screening and follow-up of patients with IPMN. 2005 The WJG Press and Elsevier Inc. All rights reserved