Cytological analysis of small branch-duct intraductal papillary mucinous neoplasms provides a more accurate risk assessment of malignancy than symptoms

Intraductal papillary mucinous neoplasm of the pancreas: Cytomorphology, imaging, molecular profile, and prognosis

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) constitutes up to 20% of all pancreatic resections, and has been increasing in recent years. Histomorphological findings of IPMN are well established; however, there are not many published papers regarding the cytological findings of IPMN on fine needle aspiration (FNA) specimens. We review the cytomorphological features, molecular profile, imaging findings, and prognosis of IPMN.

METHODS

The English literature was thoroughly searched with key phrases containing IPMN.

OBSERVATIONS

IPMN is a rare entity, affecting men and women equally and is usually diagnosed at the age of 60-70 years. The characteristic imaging features include a cystic lesion with associated dilatation of the main or branch pancreatic duct, and atrophy of surrounding pancreatic parenchyma. Cytomorphological features of IPMN include papillary fragments of mucinous epithelium in a background of abundant thick extracellular mucin, a hallmark feature. IPMNs should be evaluated for high-grade dysplasia, which manifests with nuclear atypia, nuclear moulding, prominent nucleoli, nuclear irregularity, and cellular crowding. Molecular profiling of IPMN along with carcinoembryonic antigen and amylase levels is useful in predicting malignancy or high-grade dysplasia arising in IPMN. Overall, the prognosis of IPMN is excellent except in those cases with high-grade dysplasia and malignant transformation. Postoperative surveillance is required for resected IPMNs.

CONCLUSION

IPMN requires a multidisciplinary approach for management. Cytomorphological findings of IPMN on FNA, in conjunction with tumour markers in pancreatic fluid cytology and imaging findings, are of paramount importance in clinical decision-making for IPMN.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

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.

Imaging and Cytopathological Criteria Indicating Malignancy in Mucin-Producing Pancreatic Neoplasms: A Series of 68 Histopathologically Confirmed Cases

OBJECTIVES

This study aims to evaluate the performance of clinical, imaging, and cytopathological criteria in the identification of high-grade dysplasia/carcinoma (HGD/Ca) in pancreatic mucin-producing cystic neoplasms.

METHODS

Sixty-eight consecutive, histopathologically confirmed mucin-producing cystic neoplasms, evaluated by endoscopic ultrasound-guided fine-needle aspiration, were enrolled; specifically, 39 branch duct intraductal papillary mucinous neoplasms (BD-IPMNs), 21 main duct IPMNs, and 8 mucinous cystic neoplasms. The associations between HGD/Ca in histopathology and findings of endoscopic ultrasound and cytology, demographic, lifestyle, and clinical parameters were evaluated, separately in IPMNs and mucinous cystic neoplasms.

RESULTS

Age 65 years or more was associated with HGD/Ca in IPMNs. In BD-IPMNs, cyst diameter 3 cm or greater (sensitivity, 68.8%; specificity, 65.2%), a mural nodule (sensitivity, 56.3%; specificity, 78.3%), main pancreatic duct diameter 5 to 9 mm (sensitivity, 50.0%; specificity, 87.0%), and suspicious cytology (sensitivity, 81.3%; specificity, 100%) signaled the presence of HGD/Ca. Similarly, in main duct IPMNs, suspicious cytology predicted HGD/Ca with high sensitivity (88.9%) and excellent specificity (100%). Regarding cytopathological criteria, in BD-IPMNs, HGD/Ca was associated with a high nuclear/cytoplasmic ratio, background necrosis, presence of papillary structures, hypochromatic nuclei, hyperchromatic nuclei, and major nuclear membrane irregularities (thickening and/or indentations).

CONCLUSIONS

Clinical, imaging, and cytopathological criteria are useful in the identification of HGD/Ca in IPMNs.

Clinicopathological and prognostic significance of MUC13 and AGR2 expression in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a primary pancreatic ductal epithelial neoplasm with the potential to develop into an invasive adenocarcinoma. This study aimed to investigate the clinicopathologic and prognostic significance of four potential biomarkers for the preoperative evaluation of patients with IPMN.

MATERIALS AND METHODS

Clinicopathologic materials from 104 patients with IPMN who underwent surgical resection at Jichi Medical University Hospital were analyzed. IPMNs (110 lesions in total) were histologically classified into low-grade IPMN (Group 1; n = 68), high-grade IPMN (Group 2; n = 16), or IPMN with an associated invasive carcinoma (Group 3; n = 26). We evaluated the immunohistochemical expression of MUC13, AGR2, FUT8, and FXYD3, which were previously reported to be overexpressed in pancreatic ductal adenocarcinoma.

RESULTS

The expression of MUC13 was more common in Group 3 compared with groups 1 and 2 (p < 0.001) and was associated with poor prognosis (p = 0.004). The expression of MUC13 was not associated with age, sex, tumor location, histological subtype, lymphatic or vascular invasion, or neural invasion. In most cases of IPMN, the loss of expression of AGR2 appeared to show an association with tumor recurrence and poorly differentiated histology of invasive carcinoma; however, this association was not statistically significant. The expressions of FUT8 and FXYD3were not associated with the clinicopathological features of IPMNs.

CONCLUSIONS

The results suggest that MUC13 overexpression and loss of expression of AGR2 may predict the progression of IPMN and an unfavorable prognosis in patients with IPMN.

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.

Pancreatic Cytopathology

Pancreatic cytopathology, particularly through the use of endoscopic ultrasound-guided fine-needle aspiration (FNA), has excellent specificity and sensitivity for the diagnosis of pancreatic lesions. Such diagnoses can help guide preoperative management of patients, provide prognostic information, and confirm diagnoses in patients who are not surgical candidates. Furthermore, FNA can be used to obtain cyst fluid for ancillary tests that can improve the diagnosis of cystic lesions. In this article, we describe the cytomorphological features and differential diagnoses of the most commonly encountered pancreatic lesions on FNA.

Next-generation sequencing adds value to the preoperative diagnosis of pancreatic cysts

BACKGROUND

The diagnosis of a pancreatic cyst as mucinous or high-risk dictates the need for follow-up or surgery. Molecular analysis of aspirated pancreatic cyst fluid (PCF) can provide valuable information not obtained by carcinoembryonic antigen (CEA) analysis or cytology.

METHODS

All patients who underwent molecular analysis of PCF between March 2013 and June 2015 were reviewed, including pathology, imaging, and follow-up. Molecular testing was performed using a patented, anchored multiplex polymerase chain reaction next-generation sequencing (NGS) platform, which sequenced numerous hotspots in 39 genes linked with malignancy. Performance of NGS and cytology was calculated using final outcome, as determined by clinicopathologic follow-up.

RESULTS

The study cohort included 113 PCFs from 105 patients. In total, 119 variants were detected in 67 PCFs (59%). Variants were more common in intraductal papillary mucinous neoplasms (IPMNs)/cancer than in nonmucinous cysts (P < .005). The inclusion of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS)/guanine nucleotide-binding protein (GNAS) variants improved the classification of IPMNs as mucinous from 50% by microscopy to 100%. Seventy-five percent of cancers had high-grade atypia versus 0% of IPMNs and nonmucinous cysts (P < .002). Variants in tumor protein 53 (TP53), SMAD family member 4 (SMAD4), cyclin-dependent kinase inhibitor 2A (CDKN2A), and notch1 (NOTCH1) were detected only in malignant cysts. Cytology was similarly specific (100%) for detecting malignant cysts but was more sensitive than the identification of late mutations by NGS (75% vs 46%).

CONCLUSIONS

The detection of KRAS/GNAS variants improves the identification of mucinous neoplasms. Variants in TP53, SMAD4, CDKN2A, and NOTCH1 support the diagnosis of a high-risk cyst requiring surgery or additional sampling. Although molecular analysis is not a replacement for cytopathology, it does provide valuable information for accurate preoperative diagnosis, helping to classify mucinous neoplasms and high-risk cysts that require surgical resection. Cancer Cytopathol 2017;125:41-47. © 2016 American Cancer Society.

Management of branch-duct intraductal papillary mucinous neoplasms: a large single-center study to assess predictors of malignancy and long-term outcomes

BACKGROUND AND AIMS

Management of branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) remains challenging. We determined factors associated with malignancy in BD-IPMNs and long-term outcomes.

METHODS

This retrospective cohort study included all patients with established BD-IPMNs by the International Consensus Guidelines (ICG) 2012 and/or pathologically confirmed BD-IPMNs in a tertiary care referral center between 2001 and 2013. Main outcome measures were the association between high-risk stigmata (HRS)/worrisome features (WFs) of the ICG 2012 and malignant BD-IPMNs, performance characteristics of EUS-FNA for the diagnosis of malignant BD-IPMNs, and recurrence and long-term outcomes of BD-IPMN patients undergoing surgery or imaging surveillance.

RESULTS

Of 364 BD-IPMN patients, 229 underwent imaging surveillance and 135 underwent surgery. Among the 135 resected BD-IPMNs, HRS/WFs on CT/magnetic resonance imaging (MRI) were similar between the benign and malignant groups, but main pancreatic duct (MPD) dilation (5-9 mm) was more frequently identified in malignant lesions. On EUS-FNA, mural nodules, MPD features suspicious for involvement, and suspicious/positive malignant cytology were more frequently detected in the malignant group with a sensitivity, specificity, and accuracy of 33%, 94%, and 86%; 42%, 91%, and 83%; and 33% 91%, and 82%, respectively. Mural nodules identified by EUS were missed by CT/MRI in 28% in the malignant group. Patients with malignant lesions had a higher risk of any IPMN recurrence during a mean follow-up period of 131 months (P = .01).

CONCLUSIONS

Among HRS and WFs of the ICG 2012, an MPD size of 5 to 9 mm on CT/MRI was associated with malignant BD-IPMNs. EUS features including mural nodules, MPD features suspicious for involvement, and suspicious/malignant cytology were accurate and highly specific for malignant BD-IPMNs. Our study highlights the incremental value of EUS-FNA over imaging in identifying malignant BD-IPMNs, particularly in patients without WFs and those with smaller cysts. Benign IPMN recurrence was observed in some patients up to 8 years after resection.

Interobserver agreement in the cytologic grading of atypia in neoplastic pancreatic mucinous cysts with the 2-tiered approach

BACKGROUND

The accurate cytologic grading of epithelial atypia in fine-needle aspirates of pancreatic mucinous cysts has important implications for clinical management. The Papanicolaou Society of Cytopathology has recommended a 2-tiered system of low-grade (LG) and high-grade (HG) for grading this atypia. Using this approach, this study examined the interobserver agreement within a group of cytopathologists at the Cleveland Clinic.

METHODS

Twenty cases of fine-needle aspiration of pancreatic neoplastic mucinous cysts with documented histologic follow-up and representative lesional cells were selected. Blinded to the histologic outcome, 4 cytopathologists were independently asked to assign the highest grade of atypia with the 2-tiered system of LG and HG atypia for these cases. The interobserver agreement was calculated with the κ statistic.

RESULTS

The overall raw agreement in the grading of atypia was 60%. The overall chance-adjusted agreement was fair (κ = 0.28). On the basis of the histologic outcomes, the cases were stratified into group A (HG dysplasia or worse) and group B (LG or intermediate-grade [IG] dysplasia on follow-up). Group A (n = 12) showed good chance-adjusted agreement (κ = 0.65). For group B, the chance-adjusted agreement among the observers was poor (κ = 0.03).

CONCLUSIONS

This study shows that the cytologic recognition of HG dysplasia or worse as HG atypia in pancreatic mucinous cysts has a good degree of interobserver reproducibility among cytopathologists. In contrast, a problematic area with a lack of agreement appears to be the cytologic recognition of LG and IG dysplasia as LG atypia. Additional studies with the development of reproducible criteria and educational tools may help with this challenging distinction. Cancer Cytopathol 2016;124:909-916. © 2016 American Cancer Society.

International consensus on the management of intraductal papillary mucinous neoplasm of the pancreas

International consensus guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) of the pancreas revised in 2012 (Fukuoka consensus) seem to be accepted well worldwide. Division of various factors to predict malignant transformation into two categories, i.e., "high-risk stigmata" and "worrisome features", is also accepted as practically useful for stratifying the risk factors. Our current interest resides in the development of noninvasive and/or invasive pancreatic cancer in areas of the pancreas distinct from IPMN. Invasive pancreatic cancers derived from and concomitant with IPMN should be distinguished to clarify the incidence of each entity, although some more definitive method for differentiation has to be devised in some cases where histological distinction is obscure. IPMN is a clue to early detection of pancreatic cancer. The optimal surveillance protocol for IPMN on observation should be determined in consideration of both of these different pancreatic cancers.

Role of endoscopic ultrasound-guided fine-needle aspiration cytology, viscosity, and carcinoembryonic antigen in pancreatic cyst fluid

Due to the advances and increased utility of abdominal cross-sectional imaging, the diagnosis of pancreatic cysts continues to increase. Many endosonographers, pancreatologists, and surgeons consider endoscopic ultrasound (EUS) to be an essential tool in the management of pancreatic cystic lesions (PCLs). EUS can help distinguish between mucinous and nonmucinous lesions and may identify the specific cyst type. EUS achieves these goals by delineating the cyst morphology, identifying high risk stigmata and worrisome features, and through image-guided fine-needle aspiration (FNA) and cyst fluid analysis. However, recent consensus statements have called to question the utility and diminished the role of EUS in this setting. The aim of this review is to assess the role and advances of EUS-FNA in pancreatic cyst fluid analysis, specifically in terms of fluid cytology, viscosity, and carcinoembryonic antigen (CEA) analysis.

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.

Pancreatic Resection for Side-Branch Intraductal Papillary Mucinous Neoplasm (SB-IPMN): a Contemporary Single-Institution Experience

BACKGROUND

Given the malignant potential of main duct intraductal papillary mucinous neoplasm (M-IPMN), surgical resection is generally indicated. With regard to side-branch intraductal papillary mucinous neoplasm (SB-IPMN), resection vs. observation is a topic of debate. Further review of SB-IPMN is necessary to clarify appropriate management. The primary focus of this project is to determine the incidence of malignant final pathology for patients undergoing surgery for isolated SB-IPMN with non-malignant fine-needle aspiration (FNA) cytology. We also sought to describe the relationship between factors considered in the international consensus guidelines and final pathologic outcome.

METHODS

The study is a retrospective review of all patients who underwent surgical resection for intraductal papillary mucinous neoplasm (IPMN) from 2002 to 2013 at our institution. Patients with a preoperative diagnosis of isolated SB-IPMN and FNA results for non-malignant cytology were selected among this surgical cohort for further analysis of preoperative clinical characteristics and outcomes.

RESULTS

A total of 137 patients undergoing resection for IPMN were identified. Of these, 81 patients (59%) had a component of M-IPMN or invasive disease on FNA, leaving 66 (46%) patients with SB-IPMN and non-malignant cytology. Invasive adenocarcinoma was found in 8/66 (12%) patients and high-grade dysplasia (HGD) in 4/66 (8%) patients. The mean [SD] diameter of benign SB-IPMN was 2.0 cm [1.1] (range 0.3-5.7) vs. that of HGD/invasive disease which was 3.1 cm [1.3] (range 1.5-6.0; P = 0.014). Of the 12 patients found to have HGD or invasive disease, symptoms, mural nodules, and septations were found in 7 (58%), 5 (42%), and 6 (50%), respectively. Tumor staging were as follows: IA (2), IB (2), 2A (4), and 2B (1).

CONCLUSION

With proper selection criteria, SB-IPMN is associated with a low rate of invasive pancreatic ductal adenocarcinoma at the time of resection. Nevertheless, given the demonstrated incidence of malignancy, appropriate operative candidates should undergo resection.

Intraductal papillary mucinous neoplasms

PURPOSE OF REVIEW

Our understanding of intraductal papillary mucinous neoplasm (IPMN) of the pancreas has remarkably grown within the last decade; nonetheless there is still an ongoing controversy if the majority of these potentially malignant neoplasms need to be resected or if observation in a subset is well tolerated.

RECENT FINDINGS

Novel cyst fluid biomarkers, like Gnas mutations or mab DAS-1, could play a pivotal role in the distinction of IPMN vs. other cystic lesions, in the sub-classification of IPMN and in the detection of IPMN with high-grade dysplasia or invasive cancer. Other recent studies focused on natural history of minimal- and extensive-mixed IPMN and the safety of the 2012 AIP guidelines. Small series also described that observation can be an option in selected frail patients with MD-IPMN. Further, data from a large European multicenter study analysis indicated that patients with IPMN do not have an increased frequency of extrapancreatic malignancies.

SUMMARY

Increasing knowledge about the nature of IPMN and their subtypes has resulted in an individualized approach in diagnosis and treatment. Owing to the availability of accurate diagnostic instruments, timing and indication for pancreatic resection have become more selective, sparing patients with harmless IPMN from major surgery.

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.

mAb Das-1 is specific for high-risk and malignant intraductal papillary mucinous neoplasm (IPMN)

OBJECTIVE

Intraductal papillary mucinous neoplasm (IPMN) consists of four epithelial subtypes that correlate with histological grades and risks for malignant transformation. mAb Das-1 is a monoclonal antibody against a colonic epithelial phenotype that is reactive to premalignant conditions of the upper GI tract. We sought to assess the ability of mAb Das-1 to identify IPMN with high risk of malignant transformation.

DESIGN

mAb Das-1 reactivity was evaluated in 94 patients with IPMNs by immunohistochemistry. Lesional fluid from 38 separate patients with IPMN (n=27), low-grade non-mucinous cystic neoplasms (n=7) and pseudocysts (n=4) was analysed by ELISA and western blot.

RESULTS

Immunohistochemistry-Normal pancreatic ducts were non-reactive and low-grade gastric-type IPMN (IPMN-G) (1/17) and intermediate-grade IPMN-G (1/23) were minimally reactive with mAb Das-1. In contrast, mAb Das-1 reactivity was significantly higher in high-risk/malignant lesions (p<0.0001) including: intestinal-type IPMN with intermediate-grade dysplasia (9/10); high-grade dysplasia of gastric (4/7), intestinal (12/12), oncocytic (2/2) and pancreatobiliary types (2/2); and invasive tubular (8/12), colloid (7/7) and oncocytic (2/2) carcinoma. The sensitivity and specificity of mAb Das-1 for high-risk/malignant IPMNs were 85% and 95%, respectively. Lesional fluid-Samples from low- and intermediate-grade IPMN-G (n=9), and other low-grade/benign non-mucinous lesions demonstrated little reactivity with mAb Das-1. Conversely, cyst fluid from high-risk/malignant IPMNs (n=18) expressed significantly higher reactivity (p<0.0001). The sensitivity and specificity of mAbDas-1 in detecting high-risk/malignant IPMNs were 89% and 100%, respectively.

CONCLUSIONS

mAb Das-1 reacts with high specificity to tissue and cyst fluid from high-risk/malignant IPMNs and thus may help in preoperative clinical risk stratification.

Moving beyond morphology: new insights into the characterization and management of cystic pancreatic lesions

The frequency of detection of cystic pancreatic lesions with cross-sectional imaging, particularly with multidetector computed tomography, magnetic resonance (MR) imaging, and MR cholangiopancreatography, is increasing, and many of these cystic pancreatic lesions are being detected incidentally in asymptomatic patients. Because there is considerable overlap in the cross-sectional imaging findings of cystic pancreatic lesions, and because many of these lesions being detected are smaller than 3 cm in diameter and lack any specific cross-sectional imaging features, it has become difficult to make informed decisions about patient management when the precise diagnosis remains uncertain. This article presents the limitations of cross-sectional imaging in patients with cystic pancreatic lesions, details advances in knowledge of the genomic and epigenomic changes that lead to progression of carcinogenesis, outlines the current understanding of the natural history of mucinous cystic lesions, and includes the current use and future potential of novel tumor markers and molecular analysis to characterize cystic pancreatic lesions more precisely. The need to move beyond cross-sectional imaging morphology and toward the use of new techniques to diagnose these lesions accurately is emphasized. An algorithm that uses these techniques is proposed and will hopefully lead to improved patient management.

Small-sized, flat-type invasive branch duct intraductal papillary mucinous neoplasm: a case report

Recent improvements in diagnostic modalities are increasing the frequency of detection of small-sized branch duct intraductal papillary mucinous neoplasms (BD-IPMNs). International consensus guidelines for IPMN recommend surveillance without immediate resection for small-sized (<3 cm) BD-IPMNs without malignant features on imaging. Our patient is the first to have undergone resection of a small-sized BD-IPMN containing invasive cancer, but without malignant features on imaging. We herein report a case involving a 70-year-old man with a small cystic lesion in the pancreas head detected by health screening ultrasonography. Detailed examination revealed that the cystic lesion was a BD-IPMN measuring about 2 cm, with no malignant features. However, cytological examination of the pancreatic juice showed atypical cells with high-grade dysplasia storing intracytoplasmic mucin, indicating malignant BD-IPMN. Pathological examination of the resected specimen showed a BD-IPMN measuring 16 mm with an associated invasive carcinoma that invaded the pancreatic parenchyma over a distance of 11 mm. In this patient, invasive cancer was present within a small BD-IPMN with no high-risk stigmata on imaging. Cytological examination of the pancreatic juice allowed for the detection of pancreatic cancer in such a small-sized IPMN. Although routine endoscopic retrograde cholangiopancreatography (ERCP) with cytology is not recommended in all patients with BD-IPMNs, ERCP may contribute to the detection of small pancreatic cancers in select cases. Accumulation of cases of pancreatic cancer within small BD-IPMNs may help establish the indications for ERCP with cytological examination for the purpose of early detection of small pancreatic cancer.

High-grade dysplasia and adenocarcinoma are frequent in side-branch intraductal papillary mucinous neoplasm measuring less than 3 cm on endoscopic ultrasound

BACKGROUND

Surgical resection for intraductal papillary mucinous neoplasm (IPMN) of the pancreas has increased over the last decade. While IPMN with main duct communication are generally recommended for resection, indications for resection of side-branch IPMN (SDIPMN) have been less clear. We reviewed our single institutional experience with SDIPMN and indications for resection.

METHODS

Patients who underwent resection for IPMN were identified from a prospectively maintained IRB-approved database. Patients with main pancreatic duct communication were excluded. Outcome, clinical and pathologic characteristics were correlated with endoscopic ultrasound (EUS) findings.

RESULTS

From 2000 to 2010, 105 patients who underwent preoperative EUS evaluation and resection for SDIPMN were identified. The mean age was within the sixth decade of life, and there was a slight female predominance (55 vs. 45 %). The most common presenting symptom was abdominal pain (N = 47, 45 %), followed by jaundice (N = 24, 23 %) and weight loss (N = 24, 23 %). Only ten patients (10 %) were asymptomatic at presentation; seven (70 %) had suspicious features on EUS. Of the total cohort, few patients had intracystic septations (N = 27, 26 %) or presence of mural nodules (N = 2, 2 %) on EUS. Of 39 patients who had invasive pancreatic ductal adenocarcinoma (PDAC) on final pathology, EUS-fine needle aspiration (EUS-FNA) demonstrated malignancy in only 21 (54 %). An additional seven (18 %) had EUS-FNA findings of atypia or concern for mucinous neoplasm. EUS evaluation of cyst size was correlated with final pathology. Of 70 patients with EUS cyst size <3 cm, 12 (17 %) had a preoperative EUS diagnosis of malignancy. Final pathology revealed 24 (34 %) to have PDAC: 1 of 7 (14 %) patients with cyst size <1 cm, 2 of 19 (11 %) with cyst size 1-2 cm, and 21of 44 (48 %) with cyst size 2-3 cm. Fifteen of 35 (43 %) patients with cyst size >3 cm had PDAC on final pathology. Of the patients with cyst size <3 cm, 16 (23 %) had high-grade dysplasia on final pathology: 3 of 7 (43 %) with cyst size <1 cm, 3 of 19 (16 %) with cyst size 1-2 cm, and 10 of 44 (23 %) with cyst size 2-3 cm. Seven of 35 (20 %) patients with cyst size >3 cm had high-grade dysplasia on final pathology. Although overall survival (OS) at 48 months stratified by EUS cyst size did not significantly differ between groups, patients with PDAC on final pathology had significantly worse OS compared to noninvasive pathology. A total of eight patients (8 %) developed recurrent disease, all of whom had PDAC on final pathology.

CONCLUSION

EUS is a helpful modality for the diagnostic evaluation of SDIPMN. Considering the high incidence of malignancy as well as high-grade dysplasia in SDIPMN greater than 2 cm, EUS features should be used in conjunction with other clinical criteria to guide management decisions. Patients with SDIPMN greater than 2 cm that do not undergo surgical resection may benefit from more intensive surveillance.

Intraductal papillary mucinous neoplasm of the pancreas: an update

Intraductal papillary mucinous neoplasm (IPMN) is a cystic tumor of the pancreas. The etiology is unknown, but increasing evidence suggests the involvement of several tumorigenesis pathways, including an association with hereditary syndromes. IPMN occurs more commonly in men, with the mean age at diagnosis between 64 and 67 years old. At the time of diagnosis, it may be benign, with or without dysplasia, or frankly malignant with an invasive carcinoma. Tumors arising from the main pancreatic duct are termed main-duct IPMNs, those involving the branch ducts, branch-duct IPMNs. In general, small branch-duct IPMNs are benign, particularly in asymptomatic patients, and can be safely followed. In contrast, main-duct tumors should be surgically resected and examined carefully for an invasive component. In the absence of invasion, patient's survival is excellent, from 94 to 100%. For patients with an IPMN-associated invasive carcinoma, the prognosis overall is better than those with a de novo pancreatic ductal adenocarcinoma, with a 5-year survival of 40% to 60% in some series. However, no survival advantage can be demonstrated if the invasive component in an IPMN patient is that of the conventional tubular type (versus mucinous carcinoma). Several histomorphologic variants are recognized, although the clinical significance of this "subtyping" is not well defined.

Thank you reviewers – CytoJournal 2011

CytoJournal, with its continued contribution of scientific cytopathology literature to the public domain under open access (OA) charter, thanks its dedicated peer reviewers for devoting significant efforts, time, and resources during 2011. The abstracts of poster-platform submissions to the 59^th Annual Scientific Meeting (November 2011) of the American Society of Cytopathology (ASC) in Baltimore, MD, USA, were peer reviewed by the ASC Scientific Program Committee.