Pancreatic juice cytology and subclassification of intraductal papillary mucinous neoplasms of the pancreas

Comprehensive Characterization of Intraductal Oncocytic Papillary Neoplasm of the Pancreas: A Systematic and Critical Review

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a recently recognized pancreatic tumor. Here, we aimed to determine its most essential features with the systematic review tool. PubMed, Scopus, and Embase were searched for studies reporting data on pancreatic IOPN. The clinicopathologic, immunohistochemical, and molecular data were extracted and summarized. Then, a comparative analysis of the molecular alterations of IOPN with those of pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm from reference cohorts (including The Cancer Genome Atlas) was conducted. The key findings from 414 IOPNs were as follows: 1) The male-to-female ratio was 1.5:1. Pancreatic head was the most common site (131/237; 55.3%), but a diffuse tumor extension involving more than one pancreatic segment was described in about 1 out of 5 cases (49/237; 20.6%). The mean size was 45.5 mm. An associated invasive carcinoma was present in 50% of cases (168/336). In those cases, most tumors were pT1 or pT2 and pN0 (>80%), and vascular invasion was uncommon (20.6%). Regarding survival, more than 90% of patients were alive after surgical resection. 2) Immunohistochemical and molecular features were as follows. The most commonly expressed mucins were MUC5AC (110/112; 98.2%) and MUC6 (78/84; 92.8%). Compared with pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm, the classic pancreatic drivers KRAS, TP53, CDKN2A, SMAD4, and GNAS were less altered in IOPN (P < .01). Moreover, fusions involving PRKACA or PRKACB gene were detected in all of the 68 cases examined, with PRKACB::ATP1B1 being the most common (27/68 cases; 39.7%). These genomic events emerged as an entity-defining molecular alteration of IOPN (P < .01). Thus, such fusions represent a promising biomarker for diagnostic purposes. Recent evidence also suggests their role in influencing the acquisition of oncocytic morphology. IOPN is a distinct pancreatic neoplasm with specific clinicopathologic and molecular features. Considering the clinical or prognostic implications, its recognition is essential for pathologists and, ultimately, patients' management.

Investigation of -PRKACA/-PRKACB fusion genes in oncocytic tumors of the pancreatobiliary and other systems

Intraductal oncocytic papillary neoplasms (IOPNs) of the pancreatobiliary system are tumors comprising oncocytic cells, in which three types of fusion genes involving -PRKACA/-PRKACB were recently identified. IOPNs infrequently combine with other histological subtypes of pancreatic intraductal papillary mucinous neoplasms (IPMNs) and intraductal papillary neoplasms of the bile duct (IPNBs). This study aimed to confirm the sensitivity/specificity of the fusion genes for IOPNs and to examine their significance in other oncocytic lesions. An RT-PCR, followed by DNA sequencing, was undertaken to examine the fusions in 18 histologically diagnosed IOPNs, including four combined IOPNs. Moreover, in two IOPN cases, invasive carcinomatous lesions were separately examined on their fusion status. Oncocytic thyroidal (n = 10), renal (n = 10), and salivary gland (n = 3) lesions and IPMNs (n = 9)/IPNBs (n = 4) with focal oncocytic changes were examined as controls. Fluorescence in situ hybridization using PRKACA break-apart probes was conducted for the combined IOPN cases. Target sequencing of KRAS exon2/3 and GNAS exon 8/9 was performed for IOPN cases. Fusions were detected in all IOPN cases including invasive lesions/none of the control cases. The fusion event was confirmed also in non-IOPN component in one of the four combined cases. Regarding mutation events, 5.6%/0% of IOPNs were KRAS-mt/GNAS-mt, respectively, and both components of combined IOPNs were all KRAS-wt/GNAS-wt. In conclusion, our study confirmed the sensitivity and specificity of these fusions for IOPNs. Here, we analyzed the roles of these fusion genes in combined IOPNs, proposing the possibility of IOPN development via IPMNs/IPNBs. Further studies with more combined cases are warranted.

Predictors of malignancy in main duct intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND AND AIMS

The International Consensus Guidelines updated in 2017 recommended surgery to all main duct intraductal papillary mucinous neoplasms (MD-IPMNs) with the main pancreatic duct (MPD) of 10 mm or more and those with mural nodules regardless of size. The aim of the present study was to identify predictors of malignancy in MD-IPMN among preoperative factors including MPD and mural nodule size.

METHODS

Twenty-six benign MD-IPMNs (7 resected and 19 nonresected) and 32 malignant MD-IPMNs (31 resected and 1 nonresected) were included in the study. MRCP, CT, EUS, and cytology were performed using pancreatic juice collected by endoscopic retrograde pancrestography (ERP). Resected IPMNs were classified as benign or malignant by histologic examination and nonresected MD-IPMNs by imaging, cytology, and observation. Cutoff values of candidate parameters were determined by receiver operating characteristic curves. Univariate and multivariate analyses by regression model were performed.

RESULTS

MPD and mural nodule size and cytology results differed significantly between benign and malignant groups. Cutoff values of MPD and mural nodule sizes were 15 mm and 10 mm with areas under the curve of .66 and .86, respectively. Mural nodules of 10 mm or more (odds ratio, 8.32; 95% confidence interval, 1.13-61.2; P = .038) and positive cytology (odds ratio, 42.5; 95% confidence interval, 4.10-439; P = .002) were shown to be independent predictors of malignancy by multivariate analysis. When MD-IPMNs with either predictor were diagnosed to be malignant, sensitivities, specificities, and overall accuracy for malignancy were 94%, 85%, and 90%, respectively.

CONCLUSIONS

Mural nodules of 10 mm or more and positive cytology were independent predictors of malignancy in MD-IPMN.

Relevance of gene mutations and methylation to the growth of pancreatic intraductal papillary mucinous neoplasms based on pyrosequencing

We aimed to assess some of the potential genetic pathways for cancer development from non-malignant intraductal papillary mucinous neoplasm (IPMN) by evaluating genetic mutations and methylation. In total, 46 dissected regions in 33 IPMN cases were analyzed and compared between malignant-potential and benign cases, or between malignant-potential and benign tissue dissected regions including low-grade IPMN dissected regions accompanied by malignant-potential regions. Several gene mutations, gene methylations, and proteins were assessed by pyrosequencing and immunohistochemical analysis. RASSF1A methylation was more frequent in malignant-potential dissected regions (p = 0.0329). LINE-1 methylation was inversely correlated with GNAS mutation (r =  - 0.3739, p = 0.0105). In cases with malignant-potential dissected regions, GNAS mutation was associated with less frequent perivascular invasion (p = 0.0128), perineural invasion (p = 0.0377), and lymph node metastasis (p = 0.0377) but significantly longer overall survival, compared to malignant-potential cases without GNAS mutation (p = 0.0419). The presence of concordant KRAS and GNAS mutations in the malignant-potential and benign dissected regions were more frequent among branch-duct IPMN cases than among the other types (p = 0.0319). Methylation of RASSF1A, CDKN2A, and LINE-1 and GNAS mutation may be relevant to cancer development, IPMN subtypes, and cancer prognosis.

Endoscopic ultrasonography findings of pancreatic parenchyma for predicting subtypes of intraductal papillary mucinous neoplasms

BACKGROUND AND AIMS

The subtypes of intraductal papillary mucinous neoplasms (IPMNs) are closely associated with the clinicopathological behavior and recurrence after surgical resection. However, there are no established non-invasive methods to confirm the subtypes of IPMNs without surgery. The aim of this study is to predict the subtypes of IPMNs using the findings of endoscopic ultrasonography (EUS).

METHODS

Sixty-two consecutive patients with IPMNs who underwent EUS before surgery were retrospectively reviewed. The following EUS findings were analyzed and their relationship with the subtypes was evaluated: diameter of the main pancreatic duct, cyst size, number of cysts, height of mural nodule, early chronic pancreatitis (CP) finding, fatty parenchyma and atrophic parenchyma.

RESULTS

The subtypes of IPMNs were as follows: gastric (G)-type 38 (61%), intestinal (I) -type 14 (23%) and pancreatobiliary (PB) -type 10 (16%). Fatty parenchyma was significantly associated with G-type (P < 0.0001). Early CP findings ≥2 and atrophic parenchyma were significantly correlated with I-type (P < 0.0001). PB-type was significantly associated with pancreatic parenchyma without early CP findings or fatty degeneration in comparison to the other subtypes (P < 0.0001). Using the above characteristic EUS findings, the sensitivity, specificity, and accuracy were as follows: 63%, 92% and 74%, respectively, in G-type, 57%, 96% and 87% in I-type, and 90%, 94% and 94% in PB-type.

CONCLUSIONS

The evaluation of EUS findings, especially focused on the pancreatic parenchyma, has the potential to predict the subtypes of IPMN.

A retrospective study of histological outcome for IPMN after surgery in Lausanne, Switzerland: A case series

Introduction

Intraductal papillary mucinous neoplasm (IPMN) is a 21st century concept and its management is still controversial. Strong guidelines suggest that surgery is the safest way to prevent malignant evolution. Though the risk of neoplasia is still debated, high-morbidity and mortality surgery must be proposed for high-risk patients to prevent malignant and most likely fatal pancreatic neoplasia.

Methods

The aim of this study was to analyze histological results of patients who underwent operation for IPMN under the Sendai and Fukuoka guidelines. From January 2005 to August 2016, 491 consecutive patients who underwent pancreatic resection in Lausanne University Hospital were analyzed, including 18 IPMN with surgical indication according to the Sendai and Fukuoka criteria.

Results

Thirteen (68.4%) patients had benign histopathology after surgery (the non-malignant group). Of the patients with malignant pathology, four (21%) had high-grade dysplasia and two (20.1%) had invasive carcinoma (the malignant group). The median patient age (p = 0.011) and preoperative Carbohydrate Antigen 19–9 (CA19-9) (p = 0.030) were significantly higher in the malignant group than in the non-malignant group.

Discussion

The use of the current criteria is adequate, but it may be resulting in surgery on excessive numbers of patients with IPMN. A modern decision-making strategy should be based on clinical features, precise imaging data, and biological markers.

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IPMNs are pre-cancerous tumors with a potential evolution to malignant neoplasm.

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Revised guidelines can lead to surgical decision but with high morbidity and mortality linked to pancreatic surgery.

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Moderns biological markers can help to adjust surgical criteria, added to clinical and imaging features.

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More specific criteria are needed prior to resection, and could lead to more and more conservative management.

Elevating pancreatic cystic lesion stratification: Current and future pancreatic cancer biomarker(s)

Pancreatic ductal adenocarcinoma (PDAC) is an incredibly deadly disease with a 5-year survival rate of 9%. The presence of pancreatic cystic lesions (PCLs) confers an increased likelihood of future pancreatic cancer in patients placing them in a high-risk category. Discerning concurrent malignancy and risk of future PCL progression to cancer must be carefully and accurately determined to improve survival outcomes and avoid unnecessary morbidity of pancreatic resection. Unfortunately, current image-based guidelines are inadequate to distinguish benign from malignant lesions. There continues to be a need for accurate molecular and imaging biomarker(s) capable of identifying malignant PCLs and predicting the malignant potential of PCLs to enable risk stratification and effective intervention management. This review provides an update on the current status of biomarkers from pancreatic cystic fluid, pancreatic juice, and seromic molecular analyses and discusses the potential of radiomics for differentiating PCLs harboring cancer from those that do not.

The role of pancreatic juice cytology in the diagnosis of pancreatic intraductal papillary mucinous neoplasm

BACKGROUND AND AIM

pancreatic juice cytology (PJC) is an important predictor of malignant intraductal papillary mucinous neoplasm (IPMN). This study aimed to determine the role of PJC for the prediction of malignant IPMN (intraductal papillary mucinous cancer [IPMC]).

METHODS

medical records of IPMN patients who underwent surgery between 2012 and 2016 at the Nagasaki University Hospital were reviewed. Patients who underwent preoperative PJC were classified as high risk stigmata (HRS), worrisome features (WF) and no-criteria, based on imaging criteria. PJC class III or higher was considered as positive and only invasive IPMN was defined as IPMC. PJC was validated in each group with regard to sensitivity, specificity, accuracy with the corresponding 95% confidence intervals (95% CI) and area under receiver operating curve (AUROC) analysis. A p-value of < 0.05 was considered as statistically significant.

RESULTS

preoperative pancreatic juice was obtained in 33/52 IPMN patients; only patients with adequate aspirate for cytology (n = 29) were included. In the HRS group (n = 9), 4/6 non-IPMC had a negative PJC and 3/3 IPMC had a positive PJC. In the WF group (n = 17), 9/11 non-IPMC had a negative PJC and 3/6 IPMC had a positive PJC. Adding PJC to imaging results improved the AUROCs of HRS and WF from 0.63 and 0.62 to 0.83 and 0.66, respectively. PJC was negative in all no-criteria cases (n = 3; one IPMC and two non-IPMC). In all 29 patients, PJC sensitivity was 60% (95% CI: 26%-88%), specificity was 79% (95% CI: 54%-94%), accuracy was 72% (95% CI: 63%-89%) and the AUROC was 0.69 (p = 0.03).

CONCLUSION

PJC is a statistically significant IPMC predictor that can improve the validity of imaging for IPMC prediction.

Cytologic Analysis of Pancreatic Juice Increases Specificity of Detection of Malignant IPMN-A Systematic Review

BACKGROUND & AIMS

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas can progress to cancer. Biomarkers have been identified that were reported to increase the accuracy of identification of malignant lesions; we performed a systematic review of the accuracy of these markers.

METHODS

We performed a systematic review of published studies on biomarkers of malignant IPMNs by searching MEDLINE and Web of Science databases from January 2005 through December 2017. Our methods were developed based on the Meta-analysis Of Observational Studies in Epidemiology guidelines. Pooled sensitivity, specificity, receiver operating characteristic curves, and their respective areas under the curve (AUC) were calculated from groups of markers (cell-, protein-, or DNA-based) measured in samples collected before and after surgery. A hypothetical test model was developed to determine how to meaningfully amend the revised Fukuoka guidelines, focusing on increasing test specificity for patients with IPMNs that have worrisome features.

RESULTS

We collected data from 193 published studies, comprising 12,297 patients, that analyzed 7 preoperative and 21 postoperative markers of IPMNs. The 3 biomarkers that identified malignant IPMNs with the largest AUC values were pancreatic juice cytology (AUC, 0.84; sensitivity, 0.54; specificity, 0.91), serum protein carbohydrate antigen 19-9 (AUC, 0.81; sensitivity, 0.45; specificity, 0.90), and cyst fluid cytology (AUC, 0.82; sensitivity, 0.57; specificity, 0.84). A combination of cytologic and immunohistochemical analysis of MUC1 and MUC2 in pancreatic juice samples identified malignant IPMNs with the largest AUC and sensitivity values (AUC, 0.85; sensitivity, 0.85; specificity, 0.65). In a test model, inclusion of cytologic analysis of pancreatic juice in the guideline algorithm significantly increased the specificity of detection of malignant IPMNs.

CONCLUSIONS

In a systematic review, we found cytologic analysis of pancreatic juice to have the greatest effect in increasing the specificity of detection of malignant IPMNs. We propose addition of this test to the Fukuoka guidelines for assessment of patients with IPMNs with worrisome features.

Intraductal oncocytic papillary neoplasm of the pancreas: A systematic review

BACKGROUND

Intraductal oncocytic papillary neoplasm of the pancreas (IOPN-P) is a rare subtype of intraductal papillary mucinous neoplasm (IPMN). This study was performed to summarize the clinicopathological features and management of IOPN-P.

METHODS

English-language articles were searched from MEDLINE and EMBASE from the first report of IOPN-P in 1996 until 1 May 2019 following the methodology in the PRISMA guidelines.

RESULTS

In total, 66 patients from 24 full articles were included in the final data analysis. The patients' average age was 61 years, and the male/female ratio was 1. Most lesions were large (average size, 5.50 cm), located in the pancreatic head, and found either incidentally or by uncharacteristic abdominal symptoms. IOPN-P was usually a cystic and solid lesion with or without mural nodules on radiological examination. A definitive diagnosis was often acquired from fine needle aspiration biopsy or postoperative pathology. All tumors were diagnosed as carcinoma in situ or minimally invasive carcinoma, necessitating surgical resection. The prognosis of IOPN-P was better than that of other IPMN subtypes, even when metastasis occurred. Recurrence after surgical resection of IOPN-P was rare.

CONCLUSIONS

IOPN-P is rare among IPMN subtypes with unique pathological characteristics. Because of the nontypical symptoms and radiological findings, a definitive preoperative diagnosis usually depends on multimodal examinations. Management and surveillance of IOPN-P after surgical resection should be differentiated from those of other pancreatic benign cystic lesions because of its relative malignancy, but IOPN-P should also be differentiated from other IPMN subtypes and malignant cystic tumors because of its favorable prognosis.

Subtyping of IPMN

Intraductal papillary mucinous neoplasms (IPMNs) characteristically consist of mucin-filled dilated ducts lined with neoplastic cells forming papillae with a diverse range of morphologies and varying grades of atypia. Based on morphological characteristics and immunohistochemical reaction against mucin proteins, IPMNs are classified into four distinct subtypes: gastric, intestinal, pancreatobiliary, and oncocytic. In this chapter, histomorphological criteria and techniques of immunohistochemical staining and its evaluation for subtyping IPMNs are described.

Systematic review of the clinical utility and validity of the Sendai and Fukuoka Consensus Guidelines for the management of intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

This systematic review was performed to assess the clinical utility of the Sendai Consensus Guidelines (SCG) and Fukuoka Consensus Guidelines (FCG) for intraductal papillary mucinous neoplasm (IPMN).

METHODS

A computerized search of PubMed was performed to identify all the studies which evaluated the SCG and FCG in surgically resected, histologically confirmed IPMNs.

RESULTS

Ten studies evaluating the FCG, 8 evaluating the SCG and 4 evaluating both guidelines were included. In 14 studies evaluating the FCG, out of a total of 2498 neoplasms, 849 were malignant and 1649 were benign neoplasms. Pooled analysis showed that 751 of 1801 (42%) FCG+ve neoplasms were malignant and 599 neoplasms of 697 (86%) FCG-ve neoplasms were benign. PPV of the high risk and worrisome risk groups were 465/986 (47%) and 239/520 (46%) respectively. In 12 studies evaluating the SCG, 1234 neoplasms were analyzed of which 388 (31%) were malignant and 846 (69%) were benign. Pooled analysis demonstrated that 265 of 802 (33%) SCG+ve neoplasms were malignant and 238 of 266 SCG-ve (90%) neoplasms were benign.

CONCLUSION

The FCG had a higher positive predictive value (PPV) compared to the SCG. However, the negative predictive value (NPV) of the FCG was slightly lower than that of the SCG. Malignant and even invasive IPMN may be missed according to both guidelines.

Pancreatic cancer screening: Still a delusion?

Pancreatic adenocarcinoma represents the fourth most common cause of cancer mortality and death due to pancreatic cancer (PC) have increased since 2003. Its incidence has also raised about 30% in the past decade and it is expected to become the second cause of cancer mortality by 2020 in the USA. Most PC present with metastatic disease and improvements in treatment outcomes for this group have been disappointing. These observations support the idea that screening to identify patients at an earlier stage might be an important strategy in improving overall PC outcomes. Many protocols have been tested, nevertheless, by now there is no effective screening program. Given the overall low incidence of disease and the current lack of accurate, inexpensive and noninvasive screening tests, the consensus is that widespread population-based screening for PC in the general population or in patients with only one affected first-degree relative is neither practicable nor indicated in most countries. However, a different scenario is screening patients with higher risk for PC, most of them with hereditary conditions predisposing the development of this neoplasia. In fact, some guidelines are now available helping to select these individuals at risk and to screen them, in order to achieve early detection of PC.

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

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

Intraductal Oncocytic Papillary Neoplasms of the Pancreas

Intraductal oncocytic papillary neoplasms (IOPNs) are cystic neoplasms with intraductal growth and complex papillae composed of oncocytic cells. IOPNs have been reported both in the pancreas and biliary tree, and are most likely closely related in these 2 locations. In the pancreas, these rare tumors are now considered 1 of the 4 histologic subtypes of intraductal papillary mucinous neoplasm (IPMN). Significant differences in histology, immunophenotype, and molecular genetics have been reported between IOPNs and other IPMN subtypes. However, there are limited data regarding the clinical behavior and prognosis of IOPNs in comparison to other subtypes of IPMN. We review features of pancreatic IOPNs and discuss the differential diagnosis of other intraductal lesions in the pancreas.

A case of MUC5AC-positive intraductal neoplasm of the pancreas classified as an intraductal tubulopapillary neoplasm?

This report describes a unique case of intraductal tubulopapillary neoplasm (ITPN) of the pancreas in order to clarify its oncogenesis and more precisely classify pancreatic intraductal neoplasms. A 74-year-old man visited our institution for follow-up of acute pancreatitis. Imaging examinations revealed a hypovascular intraductal mass in the head of the pancreas with progressive dilation of the pancreatic duct, atrophy of the pancreatic parenchyma, and a non-mucinous appearance. A pancreatoduodenectomy was performed to identify this pancreatic intraductal neoplasm. Macroscopically, the tumor was a solid nodular mass with no visibly secreted mucin obstructing the dilated ducts. Histologically, it had a homogeneous appearance with nodules of back-to-back tubular glands and occasional papillary elements, and there were no apparent transitions to areas with less marked cytoarchitectural atypia. Although the intraductal neoplastic growth corresponded to an ITPN, immunohistochemical staining revealed partial positivity for MUC5AC, for which ITPNs are characteristically negative. Somatic mutations in KRAS, GNAS, BRAF, and PIK3CA were not detected. A loss of MUC5AC expression and mutations in KRAS and GNAS are key elements in the diagnosis of ITPN. Thus, it was difficult to distinguish the present case as a pancreatobiliary-type (PB-type) intraductal papillary mucinous neoplasm (IPMN) or a phenotypic variant of ITPN. As it is possible that some cases of PB-type IPMN and ITPN overlap, the precise classification of these rare lesions may require re-evaluation.

Malignant transformation and overall survival of morphological subtypes of intraductal papillary mucinous neoplasms of the pancreas: A network meta-analysis

BACKGROUND

Emerging evidence suggests the predictive role of morphological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) of intraductal papillary mucinous neoplasms (IPMNs) in malignant transformation and overall survival. But results of these studies are currently discordant.

METHODS

A comprehensive literature search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) was conducted for eligible studies. Network meta-analysis using the random-effect model was carried out to detect differences in incidences of invasive IPMNs and hazard ratios from survival curves among four morphological subtypes.

RESULTS

19 studies were included in the network comparison. The outcomes showed that pancreatobiliary-type (OR for odds ratio=25.87, 95% CI: 12.11-52.10, compared with gastric-type) and oncocytic-type (OR=18.59, 95% CI: 7.18-42.74) IPMNs had the highest risks of progressing to invasive IPMNs, followed by intestinal-type (OR=5.71, 95% CI: 2.85-10.61) and gastric-type IPMNs. With the gastric type as the baseline, pancreatobiliary-type IPMNs were found to have the worst prognosis (HR for hazard ratio=5.05, 95% CrI: 1.33-13.47) while no significant differences were found for the intestinal type (HR=1.90, 95% CrI: 0.59-4.58) and the oncocytic type (HR=3.29, 95% CrI: 0.75-9.71).

CONCLUSION

It is suggested that pancreatobiliary-type IPMNs are the most likely to become invasive and are associated with poor prognosis. In contrast, the other three subtypes have similar overall survivals even though the oncocytic- and intestinal-type IPMNs are predisposed to be more invasive than gastric-type IPMNs.

Cytopathologic diagnosis of oncocytic type intraductal papillary mucinous neoplasm: Criteria and clinical implications of accurate diagnosis

BACKGROUND

Cytologic findings of pancreatic oncocytic-type intraductal papillary mucinous neoplasms (IPMNs)/intraductal oncocytic papillary neoplasms (IOPNs) are largely unknown.

METHODS

Five IOPNs encountered by the authors were analyzed.

RESULTS

Four IOPNs were located in the pancreatic head, and 1 was located in the pancreatic body/tail in 2 men and 3 women ages 56 to 84 years (mean age, 66 years). Radiologic diagnoses included pancreatic ductal adenocarcinoma (PDAC) in 2 patients, invasive cancer associated with IPMN in 1 patient, IPMN versus mucinous cystic neoplasm in 1 patient, and cystic mass in 1 patient. Cytologic findings included: hypercellular smears (4 of 5 cases) containing well formed clusters of oncocytic cells (5 of 5 cases) with prominent, slightly eccentric nucleoli (4 of 5 cases), predominantly arranged in sheets/papillary units (5 of 5 cases), with punched-out intercytoplasmic spaces (4 of 5 cases), and with occasional 3-dimensional groups and focal necrosis (3 of 5 cases). The intracytoplasmic mucin and thick extracellular mucin typical of other IPMNs were observed only in 2 cases and were very limited. The mean size on resection was 4.5 cm. Invasion was observed in 3 cases (0.1, 0.3, and 2.0 cm) of tubular-type IPMN. Initial cytologic evaluation was performed by the authors in 4 of 5 cases, which were diagnosed as IOPN (n = 3) and IPMN versus cystic PDAC (n = 1). One case was initially misdiagnosed as PDAC and, on resection, proved to be noninvasive IOPN.

CONCLUSIONS

Cytologic features of IOPNs are classical, similar to their histologic counterparts, and differ significantly from other IPMN subtypes. Because of their highly complex appearance, they are often radiologically misdiagnosed as PDAC; thus, failure to recognize their characteristic features on fine-needle aspiration may lead to inappropriate treatment. Patients with IOPN have an incomparably better prognosis than patients with ordinary PDAC, even when their neoplasms are invasive.

Intraductal Papillary Mucinous Neoplasm of Pancreas

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are neoplasms that are characterized by ductal dilation, intraductal papillary growth, and thick mucus secretion. This relatively recently defined pathology is evolving in terms of its etiopathogenesis, clinical features, diagnosis, management, and treatment guidelines. A PubMed database search was performed. All the relevant abstracts in English language were reviewed and the articles in which cases of IPMN could be identified were further scrutinized. Information of IPMN was derived, and duplication of information in several articles and those with areas of persisting uncertainties were excluded. The recent consensus guidelines were examined. The reported incidence of malignancy varies from 57% to 92% in the main duct-IPMN (MD-IPMN) and from 6% to 46% in the branch duct-IPMN (BD-IPMN). The features of high-risk malignant lesions that raise concern include obstructive jaundice in a patient with a cystic lesion in the pancreatic head, the findings on radiological imaging of a mass lesion of >30 mm, enhanced solid component, and the main pancreatic duct (MPD) of size ≥10 mm; while duct size 5-9 mm and cyst size <3 mm are considered as “worrisome features.” Magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) are primary investigations in diagnosing and following up on these patients. The role of pancreatoscopy and the analysis of aspirated cystic fluid for cytology and DNA analysis is still to be established. In general, resection is recommended for most MD-IPMN, mixed variant, and symptomatic BD-IPMN. The 5-year survival of patients after surgical resection for noninvasive IPMN is reported to be at 77-100%, while for those with invasive carcinoma, it is significantly lower at 27-60%. The follow-up of these patients could vary from 6 months to 1 year and would depend on the risk stratification for invasive malignancy and the pathology of the resected specimen. The understanding of IPMN has evolved over the years. The recent guidelines have played a role in this regard.

Current roles of endoscopy in the management of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by intraductal papillary proliferation of mucin-producing epithelial cells that exhibit various degrees of dysplasia. IPMN is classified into four histological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) according to its histomorphological and immunohistochemical characteristics. Endoscopic retrograde cholangiopancreatography plays a crucial role in the evaluation of these features of IPMN. Endoscopic ultrasonography (EUS) has proven to be more sensitive than computed tomography or magnetic resonance imaging for early detection of malignancy. The present review addresses the current roles of endoscopy and related techniques in the management of IPMN. The particular focus is on diagnosing IPMN and malignancy within IPMN, detecting pancreatic cancer concomitant with IPMN, differentiating the epithelial subtypes of IPMN, determining the optimal strategy for the management of branch duct IPMN, and discussing innovative endoscopic technology related to IPMN. The disadvantages of endoscopic examinations of IPMN and different attitudes toward EUS-guided fine-needle aspiration for IPMN between Japan (negative) and other countries (active) are also discussed.

Low interobserver agreement in cytology grading of mucinous pancreatic neoplasms

BACKGROUND

Identifying high-grade features in patients with pancreatic mucinous neoplasms (MNs) is important for patient management. The reproducibility of MN cytology grading has been evaluated to a limited extent. In the current study, the authors evaluated interobserver variability in grading MNs and the identification of neoplastic mucin in endoscopic ultrasound-guided fine-needle aspiration specimens.

METHODS

A 54-case grading set was created from histologically confirmed MNs (44 MNs) and nonmucinous lesions with abundant gastrointestinal contamination (10 nonmucinous lesions). Six observers received a tutorial, reviewed prescreened slides, and recorded: 1) a diagnosis according to a 6-tiered system (TS) (nondiagnostic, atypical [ATP], mucinous cyst low grade [MCLG], mucinous cyst high grade, suspicious for adenocarcinoma, and positive for adenocarcinoma); 2) the cyst fluid carcinoembryonic antigen diagnosis (CEADX); and 3) the presence of neoplastic musin. Interobserver agreement (IOA) was evaluated by calculation of kappa coefficients (Kappa). Diagnostic accuracy was not evaluated.

RESULTS

The IOA was lowest for the 6-TS (Kappa, 0.13; P<.001). The CEADX was available for 18 cases (33%), including 6 of 24 MCLG cases (25%). CEADX modestly improved IOA for combined tiers of the 6-TS with ATP and MCLG as separate categories. The highest IOA was noted with a 3-TS (nondiagnostic, ATP/MCLG, and mucinous cyst high grade/suspicious for adenocarcinoma/positive for adenocarcinoma [Kappa, 0.28; P<.001]) and various 4-TS (Kappa, 0.22-0.23). IOA was found to be low for neoplastic mucin (Kappa = 0.15; P<.001).

CONCLUSIONS

In a study using simulated cytology practice, observers demonstrated fair IOA for grading MNs and low IOA for identifying neoplastic mucin. Knowledge of the cyst fluid CEA level was found to modestly improve the IOA for low-grade lesions.

Elevated expression level of microRNA-196a is predictive of intestinal-type intraductal papillary mucinous neoplasm of the pancreas

OBJECTIVES

Aberrant expression of several microRNAs (miRs) has been reported in various neoplasms including intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. MicroRNA-196a (miR-196a) is up-regulated in Barrett esophagus (characterized by intestinal metaplasia) and in colorectal cancer; this relationship between intestinal characteristics and miR-196a might also be applicable to intestinal-type IPMNs. The aim of this study was to evaluate whether intestinal-type IPMNs can be discriminated from non-intestinal-type IPMNs by the expression level of miR-196a in tissue and pancreatic juice samples.

METHODS

Thirty-seven formalin-fixed paraffin-embedded tissue samples (including 3 of normal pancreatic ducts) and 36 pancreatic juice samples were obtained. The expression level of miR-196a measured by quantitative reverse transcription-polymerase chain reaction assays was compared between intestinal-type and non-intestinal-type IPMNs.

RESULTS

MicroRNA-196a expression in intestinal-type IPMN tissue samples (n = 18) was significantly higher than that of non-intestinal-type IPMNs (n = 16) (P < 0.001). Similarly, miR-196a expression in pancreatic juice samples of intestinal-type IPMNs (n = 6) was significantly higher than that of non-intestinal-type IPMNs (n = 30) (P = 0.008), and the sensitivity and specificity for prediction of intestinal-type IPMNs using pancreatic juice samples were both 83%.

CONCLUSIONS

Elevated expression of miR-196a in pancreatic juice samples is predictive of intestinal-type IPMNs.

Clinical implication of morphological subtypes in management of intraductal papillary mucinous neoplasm

PURPOSE

Morphological subtypes of intraductal papillary mucinous neoplasm (IPMN) have been established. Invasive IPMNs include colloid carcinoma and tubular carcinoma. Few studies have explored the association between the morphological and invasive subtypes in a large population. Clinical relevance of the morphological subtypes remains unclear.

METHODS

One hundred sixty-nine consecutive patients who underwent curative resection of IPMN were enrolled. The intraductal components were classified into four distinct epithelial subtypes: gastric, intestinal, pancreatobiliary, and oncocytic. The invasive components were classified as colloid or tubular.

RESULTS

The numbers of patients with gastric, intestinal, pancreatobiliary, and oncocytic subtypes were 123, 42, 3, and 1, respectively. Fifty-six patients had invasive cancer (tubular type, 42; colloid type, 14). The proportions of gastric type IPMN within each histological grade were 88 % among adenomas, 43 % among noninvasive carcinomas, 41 % among minimally invasive carcinomas, and 74 % among invasive carcinomas. Gastric subtype was more commonly associated with branch duct type and intestinal subtype with main duct type, and these tendencies were statistically significant (P = 0.0131). Furthermore, there was a strong correlation between gastric and tubular types and between intestinal and colloid types (P < 0.0001). The 5-year survival rate among the 56 invasive cancers was 52.7 % for gastric type and 89.7 % for intestinal type, which was statistically significant (P = 0.030).

CONCLUSIONS

Gastric type IPMN is mostly derived from branch duct IPMN and often demonstrates benign behavior, as seen with adenomas. However, once gastric type IPMN develops into invasive carcinoma, the survival rate is significantly lower than other types.

Immunoprofile of mucinous non-neoplastic cyst of the pancreas

BACKGROUND

A recently described mucinous non-neoplastic cyst (MNNC) of the pancreas is a benign cyst and should be distinguished from mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm (IPMN) due to different management and prognosis. The immunoprofile of MNNC has not been well studied.

DESIGN

Twenty-three MNNCs diagnosed on surgical resection were retrieved. Immunohistochemical (IHC) staining was performed on surgically resected specimen. Sixteen IPMN and 15 MCN cases were also retrieved for comparison. Cyst fluid carcinoembryonic antigen and amylase concentrations were retrieved.

RESULT

MNNCs were randomly located in the pancreas and were either unilocular or multilocular cysts that were lined by a single layer of bland columnar or cuboidal mucinous cells and supported by paucicellular stroma. The glandular epithelial cells were diffusely positive for CK7 (100%) and PDX-1 (65%); focally positive for CD10 (superficial, 65%), CD99 (basally, 100%), CDX-2 (17%), and CK20 (4%); and negative for MUC2. Only rare stromal cells in the cyst wall were weakly positive for estrogen receptor or progesterone receptor in only 6% of cases and negative for inhibin. These results were also compared with the immunoprofile of IPMN and MCN.

CONCLUSIONS

Although MNNC shares some IHC markers with IPMN or MCN, an IHC panel can help distinguish MNNC from IPMN or MCN. The results suggest that MNNC is different from IPMN and MCN.

MUC2 expression and prevalence of high-grade dysplasia and invasive carcinoma in mixed-type intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND/OBJECTIVES

Morphological types and mucin protein expressions classify intraductal papillary mucinous neoplasms (IPMNs). Main duct (MD)-IPMN mostly consists of intestinal type (I-type), which expresses MUC2. Branch duct (BD)-IPMN mostly consists of gastric type (G-type), which does not express MUC2. However, the definition of mixed-type IPMN has yet to be clarified and it contains various histological types. The aim of this study was to investigate the relationship between MUC2 expression and the presence of high-grade dysplasia (HGD) and invasive carcinoma, especially in mixed-type IPMN.

METHODS

This retrospective study included 101 consecutive patients with surgically resected IPMNs between April 2001 and October 2012. All patients were morphologically classified into four distinct types (I-type, G-type, PB-type: pancreatobilliary, O-type: oncocytic) and immunohistochemical reactivity of various anti-mucin antibodies were investigated.

RESULTS

According to the classification of the 2012 international guidelines, the numbers (and histomorphological types: I/G/PB/O) of MD, mixed-type, and BD-IPMNs were 16 (12/4/0/0), 45 (16/28/1/0), and 40 (0/38/1/1). Prevalence of MUC2 expression in MD, mixed-type, and BD-IPMNs were 75% (12/16), 36% (16/45), and 0% (0/40). In mixed-type IPMN, the prevalence of HGD and/or invasive carcinoma in MUC2-positive IPMN was significantly higher than that of MUC2-negative IPMN (HGD + invasive carcinoma: 88% vs. 38%, p = 0.0017; invasive carcinoma: 50% vs. 21%, p = 0.042). Multivariate analysis showed that MUC2 expression is an independent predictive factor of HGD and invasive carcinoma in mixed IPMN (odds ratio 14.6, 95% CI 2.5-87.4, p = 0.003).

CONCLUSIONS

In mixed-type IPMN, MUC2 expression clearly identified HGD and invasive carcinoma and may provide most appropriate surgical indication.

Usefulness of cell block cytology for preoperative grading and typing of intraductal papillary mucinous neoplasms

BACKGROUND

Precise histological diagnosis is important for the successful management of intraductal papillary mucinous neoplasms (IPMNs).

OBJECT

The object of this study was to determine whether cell block cytology is useful for preoperative cytomorphological grading and typing of IPMNs.

METHODS

The subjects were 23 patients with IPMN from whom pancreatic juice was collected via a pancreatic catheter and who subsequently underwent pancreatic resection.

RESULTS

In 20 of the 23 cases, the quantity of cells collected for cell block cytology was sufficient to enable typing and grading of the IPMN. The rates of consistency between the results of typing and grading by cell block cytology and histological examination of the surgical specimen were 95% and 80%, respectively. Typing of the 10 main-duct/mixed-duct-type IPMNs by cell block cytology yielded 5 gastric types, 3 intestinal types, 1 oncocytic type, and 1 pancreatobiliary type, and the typing was consistent with the surgical diagnosis in all 10 cases. The results of typing of the branch-duct-type IPMNs by cell block cytology were identical to the results of histological typing in the surgical specimens in every case but one. However, the specificity of cell block cytology for grading IPMNs was 55.6%.

CONCLUSIONS

The cell block cytological findings were fairly consistent with the histopathological features of the surgical specimens, thereby indicating that cell block cytology may be useful for preoperative and typing of IPMNs, but only play a supplementary role in grading IPMNs.

Fine needle aspiration cytomorphology of mucinous nonneoplastic cyst of the pancreas

OBJECTIVES

Fine needle aspiration (FNA) cytomorphology of mucinous nonneoplastic cyst (MNNC) of the pancreas has not been described.

METHODS

Nineteen of 24 patients with surgically diagnosed MNNCs had presurgery endoscopic ultrasound (EUS)-FNA biopsy. The FNA cytomorphology was retrospectively evaluated. Cyst fluid carcinoembryonic antigen and amylase concentrations were measured.

RESULTS

Endoscopic US-FNA diagnoses ranged from unsatisfactory to suspicious for adenocarcinoma. Endoscopic US-FNA cytologic findings showed cuboidal or columnar cells arranged in flat 'honeycomb' sheets/nests (100.0%), papillary architecture (10.5%), acini formation (10.5%), 3-dimensional cluster (5.3%), abundant single cell pattern (5.3%), goblet cells (17.4%), and delicate or vacuolated (60.9%) cytoplasm variable in amount. Nuclei were round or oval and small to slightly enlarged with 1 or 2 inconspicuous nucleoli, fine granular chromatin, and smooth nuclear contour (irregular in 1 case). Nuclear grooves (43.5%) and nuclear pseudoinclusions (26.1%) were identified. Most cases showed thin mucin and thick mucin in 4 cases. Stroma was seen in 4 cases (17.4%). Degenerated cells/necrotic material and macrophages were also seen. Carcinoembryonic antigen ranged from 75.2 to 5,488 ng/ml and amylase from 19 to 28,478 U/L.

CONCLUSIONS

Recognition of FNA cytomorphology of MNNC and valuable of carcinoembryonic antigen and amylase levels in cyst fluid is critical in clinical evaluation of pancreatic cysts.

Diagnostic significance of a dilated orifice of the duodenal papilla in intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND

A dilated orifice of the duodenal papilla found during screening endoscopy or ERCP is well-known as one of the specific findings of intraductal papillary mucinous neoplasm (IPMN). However, its clinical significance is still unclear.

OBJECTIVE

To assess the diagnostic significance of a dilated orifice of the duodenal papilla and evaluate whether this could be a factor predictive of malignancy or a subtype of IPMN.

DESIGN

Retrospective study.

SETTING

University hospital.

PATIENTS

This study involved 149 patients who underwent pancreatectomy for IPMN between January 1987 and June 2011.

INTERVENTION

ERCP.

MAIN OUTCOME MEASUREMENTS

The rate of malignant and intestinal type IPMNs in patients with and without papillary dilation.

RESULTS

A dilated orifice of the duodenal papilla was significantly associated with intestinal type IPMN (P < .001), but this finding could not predict the malignant grade of IPMN (P = .13). Multivariate analysis revealed that a dilated orifice was a significant factor for predicting intestinal type in both main duct (P = .01) and branch duct IPMNs (P < .001).

LIMITATIONS

The validity of the definition of papillary dilation, selection bias, and a retrospective study.

CONCLUSION

A dilated orifice of the duodenal papilla could be a significant factor for predicting intestinal type IPMN. This may lead to better clinical management of patients with IPMN.

International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas

The international consensus guidelines for management of intraductal papillary mucinous neoplasm and mucinous cystic neoplasm of the pancreas established in 2006 have increased awareness and improved the management of these entities. During the subsequent 5 years, a considerable amount of information has been added to the literature. Based on a consensus symposium held during the 14th meeting of the International Association of Pancreatology in Fukuoka, Japan, in 2010, the working group has generated new guidelines. Since the levels of evidence for all items addressed in these guidelines are low, being 4 or 5, we still have to designate them "consensus", rather than "evidence-based", guidelines. To simplify the entire guidelines, we have adopted a statement format that differs from the 2006 guidelines, although the headings are similar to the previous guidelines, i.e., classification, investigation, indications for and methods of resection and other treatments, histological aspects, and methods of follow-up. The present guidelines include recent information and recommendations based on our current understanding, and highlight issues that remain controversial and areas where further research is required.

Molecular characteristics and biological behaviours of the oncocytic and pancreatobiliary subtypes of intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasm (IPMN) consists of four epithelial subtypes. Of those, pancreatobiliary and oncocytic types are recently recognized and relatively uncommon, and usually exhibit high-grade dysplasia. The biological properties and molecular characteristics of these two types have not been well documented. The few molecular studies of the oncocytic type showed absence of KRAS mutations commonly seen in the other subtypes, raising the possibility that the oncocytic type is distinct from the other subtypes. Thus, we examined clinicopathological features and molecular alterations of the two subtypes. The study cohort consisted of 12 pancreatobiliary and 18 oncocytic IPMN cases. KRAS, BRAF, and PIK3CA mutations and TP53, SMAD4, and β-catenin expression were analysed, and the results of molecular and clinicopathological profiles were compared between the two subtypes. KRAS mutations were identified in the oncocytic type, but less frequently than the pancreatobiliary type (17% versus 58%, p = 0.048). BRAF mutation was found in a single oncocytic tumour, and no PIK3CA mutations were seen in any of the study cohort. TP53 overexpression was less frequent in the oncocytic type than in the pancreatobiliary type (11% versus 58%, p = 0.013). Invasive components were present in 50% of the oncocytic and 92% of the pancreatobiliary types, with lymph node metastasis more frequently seen in the latter, corresponding to better outcomes in the former (5-year survival rates: 93% versus 32%, p = 0.014). Our demonstration of KRAS and BRAF mutations in the oncocytic-type IPMN supports a role for the activation of the RAS-MAPK pathway in this tumour type. However, the less frequent TP53 overexpression associated with the significantly lower rates of invasion and nodal disease in the oncocytic type correlates with better outcomes compared to the pancreatobiliary type.

Localization of the most severely dysplastic/invasive lesions and mucin phenotypes in intraductal papillary mucinous neoplasm of the pancreas

OBJECTIVE

The aim of this study was to define the relevance of mural nodules (MNs) as a "direct" indicator of malignancy of intraductal papillary mucinous neoplasm (IPMN) of the pancreas.

METHODS

Thirty-nine surgically resected IPMNs excluding obviously invasive carcinomas were examined. The distribution of the most severely dysplastic lesions was mapped on specimens. Immunohistochemical analysis for MUC1 and MUC2 was performed on sections containing the histologically predominant lesions and the most severely dysplastic areas.

RESULTS

The presence of MNs correlated well with the histological grade of IPMN (P < 0.01); however, the most severely dysplastic lesions were associated with a flat/nonelevated area rather than MNs (78.9%). In the MUC1-positive subgroup, minimally invasive carcinoma was colocalized to MNs, whereas most severely dysplastic foci including minimally invasive carcinoma with components of mucinous and tubular adenocarcinoma were observed in the areas apart from MNs in the MUC2-positive and MUC1/2-negative subgroups, respectively.

CONCLUSIONS

Although our data support the concept that MNs represent areas of higher-grade dysplasia within IPMN, development of invasive lesions from MNs may be limited to cases that are MUC1-positive. Careful attention should be paid to the emergence of invasive IPMN from flat foci in MUC2-positive and MUC1/2-negative cases.

Factors in intraductal papillary mucinous neoplasms of the pancreas predictive of lymph node metastasis

BACKGROUND

Little is known about the frequency of lymph node metastasis (LNM) in intraductal papillary mucinous neoplasms (IPMNs), and we have not been able to determine how much lymph node dissection is necessary in individual cases. The aim of this study was to investigate the predictive factors for the LNM in IPMNs.

METHODS

Medical records of 120 patients pathologically diagnosed as having IPMN were reviewed, and 16 possible predictive factors regarding the LNM were analyzed.

RESULTS

LNM was observed in 7 patients (6%), all of whom were diagnosed as having mural nodules preoperatively. Sensitivity, specificity, and accuracy of preoperative imaging for detecting mural nodules of IPMNs in this study were 84, 97, and 90%, respectively. Univariate analysis using 61 patients having mural nodules preoperatively revealed that the size of mural nodules ≥10 mm and positive imaging findings for invasive tumor and possible LNM were significant predictive factors for the LNM. Multivariate analysis demonstrated that only an imaging finding for invasive tumor was an independent significant predictive factor. Positive and negative predictive values of the imaging finding of invasive IPMNs for LNM were 50 and 98%, respectively.

CONCLUSIONS

Standard lymph node dissection would be recommended in patients with IPMNs with mural nodules demonstrating preoperative imaging findings for invasive carcinomas. and IAP.

Pancreatic cyst fluid and serum mucin levels predict dysplasia in intraductal papillary mucinous neoplasms of the pancreas

INTRODUCTION

There are no reliable markers of dysplasia in patients with incidentally discovered intraductal papillary mucinous neoplasms of the pancreas (IPMN). IPMN dysplasia may be associated with mucin protein (MUC) expression and histopathologic subtype. We hypothesize that MUC expression in cyst fluid and serum can identify lesions with high risk of malignancy.

METHODS

Cyst fluid and serum were collected from 40 patients during pancreatectomy for IPMN between 2005 and 2009. Samples were grouped into low-risk (low-grade or moderate dysplasia, n = 21) and high-risk groups (high-grade dysplasia or carcinoma, n = 19). Mucin expression (MUC1, MUC2, MUC4, and MUC5AC) was assessed utilizing enzyme-linked immunosorbent assays.

RESULTS

MUC2 and MUC4 cyst fluid concentrations were elevated in high-risk versus low-risk groups (10 ± 3.0 ng/ml vs. 4.4 ± 1.2 ng/ml, p = 0.03; 20.6 ± 10.6 ng/ml vs. 4.5 ± 1.4 ng/ml, p = 0.03, respectively). Corresponding serum samples revealed higher levels of MUC5AC in high-risk compared with low-risk patients (19.9 ± 9.3 ng/ml vs. 2.2 ± 1.1 ng/ml, p = 0.04). Histopathologic subtype was significantly associated with grade of dysplasia, and the intestinal subtype displayed increased MUC2 cyst fluid concentrations (13.8 ± 6.5 ng/ml vs. 4.1 ± 0.9 ng/ml, p = 0.02).

CONCLUSIONS

In this study, high-risk IPMN showed elevated cyst fluid concentrations of MUC2 and MUC4, and increased serum levels of MUC5AC. High-risk IPMN also displayed a distinct mucin expression profile in specific histologic subtypes. These data, if validated, may allow surgeons to more appropriately select patients for operative resection.

Controversies in the management of pancreatic IPMN

Although considerable progress has been made in our understanding of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, some issues still remain to be resolved. Uncertainty exists regarding the classification of IPMNs. The necessity of the mixed-type category of IPMN and whether such lesions should be defined radiographically or histologically needs to be determined. The preoperative distinction of branch duct IPMNs from nonmucinous cysts should be further investigated so that potentially malignant lesions can be identified and management strategies guided effectively. The role and safety of cystic fluid analysis remains to be clarified in this context. With regard to the diagnosis of malignancy in branch duct IPMNs, criteria for identifying malignancy need to be re-evaluated. The presence of mural nodules is a very reliable predictor; however, controversy exists over the value of size as a reliable indicator. Criteria with increased specificity are needed, perhaps including histological subtype of lesion, to reduce the false-positive rate of the present criteria. Finally, the best modality and interval for surveillance of branch duct IPMNs requires determination because of its significance in terms of malignant transformation, development of distinct ductal adenocarcinoma and disease recurrence after resection.

Stromal thrombospondin-1 expression is a prognostic indicator and a new marker of invasiveness in intraductal papillary-mucinous neoplasm of the pancreas

The invasion of intraductal papillary-mucinous neoplasm (IPMN) is sometimes difficult to diagnose using only ordinary hematoxylin-eosin sections. The aim of this study was to evaluate the invasion of IPMN more precisely using thrombospondin-1 (TSP1) immunohistochemistry as a useful adjunct to morphological examination. Eighty patients that underwent primary resection for pancreatic IPMNs were retrospectively analyzed. The 80 IPMNs were studied for the expression of TSP1, MUC1-CORE, MUC2, and MUC5AC. The cases were evaluated for dysplasia, the presence of invasion, hisological subtypes, and survival. The 80 IPMNs were classified into 29 intraductal papillary-mucinous adenomas (IPMAs), 10 borderline IPMNs, 18 noninvasive intraductal papillary-mucinous carcinomas (IPMCs), and 23 invasive IPMCs according to the WHO classification. Invasive IPMCs were further divided into 12 minimally invasive IPMCs (MI-IPMCs) and 11 invasive carcinomas originating from IPMCs (IC-IPMCs) according to the Japan Pancreatic Society classification. The rate of strongly positive cases with more than 30% of the cancer stroma area expressing TSP1 was significantly higher in MI-IPMC and IC-IPMC than in noninvasive IPMC (P = 0.035, 0.005). Furthermore, patients in the strongly positive group had a significantly poorer prognosis compared to patients in the negative-weakly positive group (P = 0.008, log-rank test). Of the 80 tumors, 22 were classified into gastric-, 45 into intestinal-, 7 into pancreatobiliary-, and 6 into oncocytic-type IPMNs according to criteria described previously. The cases with a strongly positive expression of TSP1 were frequently detected in the pancreatobiliary and oncocytic types (P = 0.001). In conclusion, stromal TSP1 expression is a prognostic indicator and a new marker of invasiveness in IPMN.

Intraductal oncocytic papillary carcinoma of the pancreas showing numerous hyaline globules in the lumen

Two cases of intraductal oncocytic papillary carcinoma (IOPC) treated surgically were analyzed on light microscopy and immunohistochemistry: that of a 61-year-old man and that of a 55-year-old man. There were no clinical symptoms in either case. Pancreatic abnormalities were discovered incidentally on CT. Various clinical examinations were carried out, and the preoperative diagnosis was intraductal papillary mucinous carcinoma (IPMC) in both cases. Surgery was performed. Macroscopic observation of tissue cross-sections indicated multilocular cystic mass containing polypoid lesions encapsulated by the dilated pancreatic duct. Histologically, the cyst walls were lined by columnar epithelial cells with complex papillary projections associated with oxyphilic cytoplasm, and they were strongly immunoreactive with anti-mitochondrial antibody in the cytoplasm. Electron microscopy showed numerous mitochondria in the cytoplasm. IOPC was diagnosed. Interestingly, amorphous hyaline globules were produced from the oxyphilic cells, which exhibited a bud-like appearance. The hyaline globules were not positive for mucin staining. No case of IPMC with hyaline globules has been reported to date. The production of hyaline globules may be related to oncocytic differentiation. It is suggested that hyaline globules should be regarded as a characteristic of IOPC.

Intraductal oncocytic papillary neoplasms of the pancreas and bile ducts: a description of five new cases and review based on a systematic survey of the literature

BACKGROUND

Intraductal oncocytic papillary neoplasms (IOPN) are rare tumors of the pancreatic and biliary ductal system. It is not absolutely clear if the molecular and clinicopathologic characteristics of IOPN differ significantly from other related lesions, namely intraductal papillary mucinous neoplasms (IPMN). Therefore it is not clear if it is reasonable to consider IOPN as a separate diagnostic and clinical entity.

METHODS

In order to describe the clinicopathologic characteristics of IOPN and to compare them with the IPMN profile, we performed a systematic review of the literature and additionally studied five previously unreported IOPN cases.

RESULTS

IOPN differ from IPMN by lack of K-ras gene mutations in all studied cases. Several differences in the clinical and biological profile between IOPN and IPMN exist, but they are of quantitative rather than of qualitative nature. Additionally, pancreaticobiliary or gastric-foveolar IPMN components may coexist with IOPN component within a single lesion, which suggests at least a partial relation of the pathogenetic pathways of IPMN and IOPN. Importantly, the pathogenesis of accumulation of mitochondria and oxyphilic appearance of IOPN remains unknown.

CONCLUSIONS

At present, there are no reliable criteria other than histopathological picture and K-ras gene status to differentiate IOPN from IPMN. In particular, no clear differences in optimal treatment options and prognosis between these tumors are known. Further studies are needed to clarify the biology of IOPN and to establish their position in clinicopathologic classifications of pancreatic tumors.

Predictors of the presence of concomitant invasive ductal carcinoma in intraductal papillary mucinous neoplasm of the pancreas

OBJECTIVE

Invasive ductal carcinoma (DC) of the pancreas arising as an independent lesion in association with intraductal papillary mucinous neoplasm (IPMN) has occasionally been reported. However, clinicopathological features related to the presence of DC in patients with IPMN remain largely unknown. The purpose of the present study was to determine the factors predicting the presence of concomitant DC in those with IPMN.

MATERIALS AND METHODS

We retrospectively reviewed the clinicopathological data of a consecutive series of 236 patients with IPMN treated by surgical resection or followed up at our institution between January 1987 and June 2008. In an attempt to identify predictors for the presence of DC, clinicopathological variables were compared between IPMN patients with concomitant DC and those without concomitant DC.

RESULTS

Of 236 patients with IPMN, concomitant DC was detected synchronously or metachronously in 22 patients (9.3%). All the 22 IPMNs were of branch duct type and histological grades of 12 resected IPMNs were adenoma(n = 8) and borderline (n = 4). Multivariate analysis revealed 2 significant predictive factors for the presence of DC in IPMN, including worsening diabetes mellitus (P < 0.001) and an abnormal serum CA 19-9 level (P = 0.024).

CONCLUSION

In view of the high prevalence of DC careful inspection of the entire pancreatic gland is necessary for early detection of DC in patients with branch duct IPMNs, especially when worsening diabetes mellitus and an abnormal serum CA 19-9 level are manifested.

Invasive carcinoma derived from the nonintestinal type intraductal papillary mucinous neoplasm of the pancreas has a poorer prognosis than that derived from the intestinal type

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is divided into 4 subtypes: an intestinal type, a gastric type, a pancreatobiliary type, and an oncocytic type. The purposes of this study were to clarify the outcomes and the characteristics of invasive carcinoma derived from IPMN (invasive IPMC) by focusing on these subtypes with a comparison to conventional invasive ductal carcinoma (IDC) of the pancreas.

METHODS

A total of 30 patients with invasive IPMC were reviewed, and the tumors were divided into 2 pathologic subtypes, intestinal and nonintestinal type. The prognosis and characteristics of the 2 subtypes were evaluated. Furthermore, the prognosis of 119 patients with conventional IDC was compared with that of patients with invasive carcinoma derived from the intestinal or nonintestinal type IPMN.

RESULTS

The 5-year survival rate of patients with the nonintestinal type (0.0%) was as poor as that of patients with conventional IDC (19.9%; P = .67). The patients with the intestinal type (66.7%) had a more favorable prognosis than patients with conventional IDC (P < .001). The nonintestinal type was characterized by positive lymphatic invasion and tubular invasive pattern.

CONCLUSION

Invasive carcinoma derived from the nonintestinal type IPMN characterized by lymphatic invasion and tubular invasive pattern is associated with a poor prognosis.

Pancreatic-duct-lavage cytology in candidates for surgical resection of branch-duct intraductal papillary mucinous neoplasm of the pancreas: should the International Consensus Guidelines be revised?

BACKGROUND

The International Consensus Guidelines are helpful for the management of branch-duct intraductal papillary mucinous neoplasms (IPMNs), because they allow us to exclude malignancy. However, it is not possible to predict malignancy with certainty, and further preoperative differentiation between benign and malignant IPMNs is required to avoid the false-positive results.

OBJECTIVE

To examine the usefulness of pancreatic-duct-lavage cytology by using an originally designed double-lumen catheter for discriminating benign and malignant IPMNs of the branch-duct type in candidates for surgical resection based on the International Consensus Guidelines.

PATIENTS

Pancreatic-duct-lavage cytology was investigated in 24 patients with branch-duct IPMNs who underwent surgical resection based on the International Consensus Guidelines, namely, they either had intramural nodules or the ectatic branch duct was >30 mm in diameter.

DESIGN

Single-center retrospective study.

SETTING

Academic medical center.

MAIN OUTCOME MEASUREMENTS

The sensitivity and specificity of pancreatic-duct-lavage cytology for discriminating benign from malignant IPMNs.

RESULTS

More than 30 mL of pancreatic-duct-lavage fluid was obtained from each patient, and there were no patients with noninformative results. The sensitivity, specificity, positive predictive value, and negative predictive value of the cytologic diagnosis were 78%, 93%, 88%, and 88%, respectively.

LIMITATIONS

Single-center and small number of patients.

CONCLUSIONS

Pancreatic-duct-lavage cytology can improve differentiation between benign and malignant IPMNs of the branch-duct type in candidates for surgical resection based on the International Consensus Guidelines.