Incidental pancreatic cysts on 3D turbo spin echo magnetic resonance cholangiopancreatography: prevalence and relation with clinical and imaging features

Comparison of guidelines for intraductal papillary mucinous neoplasm: What is the next step beyond the current guidelines?

Management of intraductal papillary mucinous neoplasm is controversial, and several guidelines have aimed to establish an adequate strategy for surgical resection and surveillance. We compared various intraductal papillary mucinous neoplasm guidelines and considered new matters that are pivotal for improved treatment of intraductal papillary mucinous neoplasm. We identified and compared 11 published guidelines, three of which were major guidelines that mainly referred to the diagnosis and treatment of intraductal papillary mucinous neoplasm (International Association of Pancreatology 2012 guidelines, European Study Group on Cystic Tumours of the Pancreas 2013 guidelines, and American Gastroenterological Association 2015 guidelines). The main concerns of these three guidelines were indication for surgery and follow up of non-resected lesions. Among the differences between the three guidelines, the period of surveillance recommended was the most controversial matter. Meanwhile, several nomograms have been proposed to improve the diagnosis of intraductal papillary mucinous neoplasm from the level of experts' experiences to that of rational systems. We discuss the adequate strategy of surveillance for intraductal papillary mucinous neoplasm with and without pancreatectomy and nomograms aiming to predict the risk of malignancy in patients with intraductal papillary mucinous neoplasm.

Longterm follow-up of small pancreatic cystic lesions in liver transplant recipients

Incidental small pancreatic cystic lesions (PCLs) are often found on preoperative imaging in patients undergoing orthotopic liver transplantation (OLT). Although these are considered benign or of low malignant potential, the influence of immunosuppression after OLT may be of concern. The aim of this study was to observe the longterm outcome of these small PCLs in post-OLT patients. An institutional OLT database of 1778 consecutive OLT patients from January 2000 to December 2010 was analyzed. Computed tomography, magnetic resonance imaging, or endoscopic ultrasound at the time of OLT and all subsequent imaging, cytology, fluid analysis of PCLs, and patient status were evaluated. A total of 70 patients with 182 PCLs, of benign or low malignant potential, were identified with a mean follow-up time of 64 months. At initial diagnosis of PCLs in 48 patients, 7 branch duct-type intraductal papillary mucinous neoplasms (B-IPMNs), 1 serous cystadenoma (SCA), and 40 nonspecific benign cysts were identified. Final diagnosis at the end of the follow-up revealed 16 B-IPMNs, 3 SCAs, and a mixed acinar-neuroendocrine carcinoma, in which the latter developed 9 years after initial diagnosis of B-IPMN. During the follow-up time, average increase in size and number of PCLs were 4.5 mm and 1.4, respectively (P < 0.001 for both). The majority of incidental PCLs in OLT patients showed an indolent behavior despite immunosuppression. Risk of malignancy development was very low and comparable with normal population. Liver Transplantation 23 324-329 2017 AASLD.

Diffusion-Weighted Magnetic Resonance Imaging in Distinguishing Between Mucin-Producing and Serous Pancreatic Cysts

OBJECTIVE

The aim of this study was to evaluate the feasibility and reproducibility of diffusion-weighted imaging in distinguishing between mucin-producing and serous pancreatic cysts.

METHODS

Forty-four pancreatic cysts (43 patients, 27 women; mean age, 57 years; 26 mucin-producing cysts, 18 serous cysts) that underwent histological examination or cyst analysis after diffusion-weighted magnetic resonance imaging were retrospectively reviewed. Three blinded readers independently evaluated signal intensity and apparent diffusion coefficient (ADC). Intraobserver and interobserver agreements were calculated. Fisher exact test and Welch t test were used to compare signal intensity and ADC values, respectively, with pathological results. Receiver operating characteristic analysis was used to determine diagnostic accuracy of various thresholds for ADC. A P value less than 0.05 was considered statistically significant.

RESULTS

Mean ADC values of the mucin-producing cysts were 3.26 × 10, 3.27 × 10, and 3.35 × 10 mm/s for the 3 readers, respectively. Mean ADC values of the serous cysts were 2.86 × 10, 2.85 × 10, and 2.85 × 10 mm/s for the 3 readers, respectively. Differences in ADC values between the 2 cyst groups were 12.4%, 12.9%, and 14.8% for the 3 readers, respectively (P < 0.001). Intraobserver and interobserver agreement was excellent. A threshold ADC of 3 × 10 mm/s resulted in correct identification of cysts in 77% to 81% of cases, with sensitivity and specificity ranging between 84% and 88% and 66% and 72%, respectively.

CONCLUSIONS

Diffusion-weighted imaging may be a helpful tool in distinguishing between mucin-producing and serous pancreatic cysts.

Intraductal papillary mucinous neoplasms and mucinous cystadenomas: current status and recommendations

The real prevalence of pancreatic cystic lesions remains unknown. The malignant potential of some of these lesions remains a cause for significant concern. Thus, it is mandatory to develop a strategy to clearly discriminate those cysts with a potential for malignant transformation from those that do not carry any significant risk. Intraductal papillary mucinous neoplasms and mucinous cystadenomas are mucinous cystic neoplasms with a known malignant potential that have gained greater recognition in recent years. However, despite the numerous studies that have been carried out, their differential diagnosis among other cysts subtypes and their therapeutic approach continue to be a challenge for clinicians. This review contains a critical approach of the current recommendations and management strategies regarding intraductal papillary mucinous neoplasms and mucinous cystadenomas, as well as highlighting the limitations exposed in current guidelines.

Pathology of Pancreatic Cancer Precursor Lesions

To better understand pancreatic ductal adenocarcinoma (PDAC) and improve its prognosis, it is essential to understand its origins. This article describes the pathology of the 3 well-established pancreatic cancer precursor lesions: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. Each of these precursor lesions has unique clinical findings, gross and microscopic features, and molecular aberrations. This article focuses on histopathologic diagnostic criteria and reporting guidelines. The genetics of these lesions are briefly discussed. Early detection and adequate treatment of pancreatic cancer precursor lesions has the potential to prevent pancreatic cancer and improve the prognosis of PDAC.

Pancreatic cysts in general population on ultrasonography: Prevalence and development of risk score

BACKGROUND

Pancreatic cysts are related to the presence of ductal adenocarcinomas elsewhere in the pancreas, and are also associated with an increased risk of pancreatic adenocarcinoma in the future. Most of the previous studies that investigated the prevalence of pancreatic cysts focused on patients within a hospital or out-patient setting, which may not be representative of the general population. We investigated the prevalence and predictive factors for the presence of pancreatic cysts within a large number of subjects via general health examination.

METHODS

Between December 2007 and December 2013, a total of 5198 subjects were enrolled that underwent ultrasonography (US) on general health examination. We established a scoring system for predicting the presence of one or more pancreatic cysts using a split-sample method.

RESULTS

Among the enrolled subjects, the prevalence of a pancreatic cyst was 3.5 %. In multivariate analysis, the prevalence was significantly increased with older age, female sex, and the presence of gall bladder adenomyomatosis (GB-ADM). Based on multivariate analysis in the training sample (n = 2,599), we established the scoring system consisting of age, sex, and the presence of GB-ADM to predict the presence of pancreatic cysts. This scoring system was validated in the testing sample (n = 2,599) and produced an area under the curve of 0.711.

CONCLUSIONS

The prevalence of pancreatic cyst detected by US was 3.5 % in the general population, and increased with age, female sex, and the presence of GB-ADM. A new scoring system developed in the present study may help to identify better candidates for further examination when the pancreas is not visible by US.

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

AIM

To investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms (bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography (MRCP) follow-up.

METHODS

We retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs (mean 4.4) to follow-up incidental, presumed bd-IPMN without signs of malignancy, found or confirmed at a baseline MRCP examination. Median follow-up time was 48.5 mo (range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes: (1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and (2) alert findings, defined as worrisome features and/or high risk stigmata (e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.

RESULTS

We found a total of 343 cysts (per-patient mean 5.1) with average size of 8.5 mm (range 5-25 mm). Imaging evolution was observed in 32/72 patients (44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts (13.7%). There was a main trend towards small (< 10 mm) increase and/or decrease of cysts size at a median time of 22.5 mo. Alert findings developed in 6/72 patients (8.3%; 95%CI: 3.4-17.9) over a wide interval of time (13-63 mo). No malignancy was found on endoscopic ultrasound with fine-needle aspiration (5/6 cases) or surgery (1/6 cases). No clinical or initial MRCP features were significantly associated with changes in bd-IPMN appearance (P > 0.01).

CONCLUSION

Changes in MRCP appearance of incidental bd-IPNM were frequent over the follow-up (44.4%), with relatively rare (8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging follow-up should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.

Prevalence, Diagnosis and Management of Pancreatic Cystic Neoplasms: Current Status and Future Directions

Cystic neoplasms of the pancreas are found with increasing prevalence, especially in elderly asymptomatic individuals. Although the overall risk of malignancy is very low, the presence of these pancreatic cysts is associated with a large degree of anxiety and further medical investigation due to concerns about malignancy. This review discusses the different cystic neoplasms of the pancreas and reports diagnostic strategies based on clinical features and imaging data. Surgical and nonsurgical management of the most common cystic neoplasms, based on the recently revised Sendai guidelines, is also discussed, with special reference to intraductal papillary mucinous neoplasm (IPMN; particularly the branch duct variant), which is the lesion most frequently identified incidentally. IPMN pathology, its risk for development into pancreatic ductal adenocarcinoma, the pros and cons of current guidelines for management, and the potential role of endoscopic ultrasound in determining cancer risk are discussed. Finally, surgical treatment, strategies for surveillance of pancreatic cysts, and possible future directions are discussed.

Pancreatic MRI for the surveillance of cystic neoplasms: comparison of a short with a comprehensive imaging protocol

OBJECTIVES

The study aims were to evaluate: (1) whether a short-protocol (SP) MRI for the surveillance of pancreatic cystic neoplasms (PCN) provides equivalent clinical information as a comprehensive-protocol (CP), and (2) the cost reduction from substituting CP with SP for patient surveillance.

METHODS

This retrospective study included 154 consecutive patients (median age: 66, 52 % men) with working-diagnosis of PCN and available contrast-enhanced MRI/MRCP. Three radiologists evaluated independently two imaging sets (SP/CP) per patient. The CP included: T2-weighted (HASTE/MRCP), DWI and T1-weighted (chemical-shift/pre-/post-contrast) images [acquisition time (AT) ≈ 35 min], whereas the SP included: T2-weighted HASTE and T1-weighted pre-contrast images (AT ≈ 8 min). Mean values of largest cyst/main pancreatic duct diameter (D_C/D_MPD) were compared. Agreement regarding presence/absence of cystic/MPD mural nodules (MN_C/MN_MPD), inter-observer agreement and cost differences between SP/CP were calculated.

RESULTS

For D_C and D_MPD, mean values with SP/CP were 21.4/21.7 mm and 3.52/3.58 mm, while mean differences SP-CP were 0.3 mm (p = 0.02) and 0.06 mm (p = 0.12), respectively. For presence/absence of MN_C and MN_MPD, SP/CP coincided in 93 % and 98 % of cases, respectively. Inter-observer agreement was strong for SP/CP. SP-cost was 25 % of CP-cost.

CONCLUSIONS

For the surveillance of PCN, short-protocol MRI provides information equivalent to the more time-consuming and costly comprehensive-protocol.

KEY POINTS

• Pancreatic cystic neoplasms (PCN) are increasingly diagnosed in the general population. • Multiple imaging controls are recommended for the surveillance of patients with PCN. • Short and comprehensive MRI-protocols are equivalent for decision-making in PCN under surveillance. • Evaluation of imaging risk factors in PCNs is comparable with both MRI-protocols. • Use of the short MRI-protocol may rationalise healthcare resources.

Pancreatic Cysts in Autosomal Dominant Polycystic Kidney Disease: Prevalence and Association with PKD2 Gene Mutations

Purpose To define the magnetic resonance (MR) imaging prevalence of pancreatic cysts in a cohort of patients with autosomal dominant polycystic kidney disease (ADPKD) compared with a control group without ADPKD that was matched for age, sex, and renal function. Materials and Methods In this HIPAA-compliant, institutional review board-approved study, all patients with ADPKD provided informed consent; for control subjects, informed consent was waived. Patients with ADPKD (n = 110) with mutations identified in PKD1 or PKD2 and control subjects without ADPKD or known pancreatic disease (n = 110) who were matched for age, sex, estimated glomerular filtration rate, and date of MR imaging examination were evaluated for pancreatic cysts by using axial and coronal single-shot fast spin-echo T2-weighted images obtained at 1.5 T. Total kidney volume and liver volume were measured. Univariate and multivariable logistic regression analyses were conducted to evaluate potential associations between collected variables and presence of pancreatic cysts among patients with ADPKD. The number, size, location, and imaging characteristics of the cysts were recorded. Results Patients with ADPKD were significantly more likely than control subjects to have at least one pancreatic cyst (40 of 110 patients [36%] vs 25 of 110 control subjects [23%]; P = .027). In a univariate analysis, pancreatic cysts were more prevalent in patients with ADPKD with mutations in PKD2 than in PKD1 (21 of 34 patients [62%] vs 19 of 76 patients [25%]; P = .0002). In a multivariable logistic regression model, PKD2 mutation locus was significantly associated with the presence of pancreatic cysts (P = .0004) and with liver volume (P = .038). Patients with ADPKD and a pancreatic cyst were 5.9 times more likely to have a PKD2 mutation than a PKD1 mutation after adjusting for age, race, sex, estimated glomerular filtration rate, liver volume, and total kidney volume. Conclusion Pancreatic cysts were more prevalent in patients with ADPKD with PKD2 mutation than in control subjects or patients with PKD1 mutation. (©) RSNA, 2016 Online supplemental material is available for this article.

Association Between Advances in High-Resolution Cross-Section Imaging Technologies and Increase in Prevalence of Pancreatic Cysts From 2005 to 2014

BACKGROUND & AIMS

Increasingly, pancreatic cysts are discovered incidentally in patients undergoing cross-sectional imaging for nonpancreatic reasons. It is unclear whether this increase is caused by improved detection by progressively more sophisticated cross-sectional imaging techniques or by a true increase in prevalence. We aimed to determine the prevalence of incidental pancreatic cysts in patients undergoing magnetic resonance imaging (MRI) for nonpancreatic indications on successive, increasingly sophisticated MRI systems. Also, we compared prevalence based on the demographic characteristics of the patients.

METHODS

We collected data from MRIs performed at the Mayo Clinic in Florida during the sample months of January and February, from 2005 to 2014. Each patient's clinical chart was reviewed in chronological order to include the first 50 MRIs of each year (500 total). Patients were excluded if they had pancreatic disease including cysts, pancreatic surgery, pancreatic symptoms, pancreatic indication for the imaging study, or previous abdominal MRIs. An expert pancreatic MRI radiologist reviewed each image, looking for incidental pancreatic cysts.

RESULTS

Of the 500 patients analyzed, 208 patients (41.6%) were found to have an incidental cyst. A significant relationship was observed between pancreatic cysts and patient age (P < .0001), diabetes mellitus (P = .001), and nonpancreatic cancer (P = .01), specifically nonmelanoma skin cancer (P = .03) or hepatocellular carcinoma (P = .02). The multivariable model showed a strong association between hardware and software versions and detection of cysts (P < .0001); the old hardware detected pancreatic cysts in 30.3% of patients, whereas the newest hardware detected cysts in 56.3% of patients.

CONCLUSIONS

Based on an analysis of data collected from 2005 through 2014, newer versions of MRI hardware and software corresponded with higher numbers of pancreatic cysts detected. Older age, diabetes, and the presence of nonpancreatic cancer (specifically nonmelanoma skin cancer and hepatocarcinoma) were also associated with the presence of cysts.

National trends in resection of cystic lesions of the pancreas

BACKGROUND

Management of cystic lesions of the pancreas (CLP) is controversial. In this study, we sought to evaluate national changes in the resection of CLP over time, to better understand the impact of evolving guidelines on CLP management.

METHODS

We used Medicare data to examine CLP resection among patients undergoing pancreatic resection between 2001 and 2012. Patients with a diagnosis of CLP were identified and compared to patients with non-CLP indications. We then examined changes over time in patient and hospital characteristics and outcomes among patients with a CLP diagnosis.

RESULTS

We identified 56,419 Medicare patients undergoing pancreatic resection, of which 2129 had a CLP diagnosis. The annual number of CLP resections, and proportion of all resections performed for CLP increased significantly during the period, from 2.1% (65/3072) resections in 2001, to 4.5% (286/6348) in 2012 (p < 0.001). The proportion of CLP resections with a malignant diagnosis did not change (15.5% in 2001-2003 vs. 13.1% in 2010-2012, p = 0.4). Overall rates of 30-day mortality decreased significantly during the period (9.6% in 2001-2003 vs. 5.5% in 2010-2012, p < 0.001).

DISCUSSION

CLP resections were performed with increasing frequency in Medicare patients between 2001 and 2012, but this did not correspond to increased diagnosis of malignancy. Additional research is needed to understand the influence of recent guidelines on management of CLP.

Which is the best current guideline for the diagnosis and management of cystic pancreatic neoplasms? An appraisal using evidence-based practice methods

BACKGROUND AND AIM

Cystic pancreatic neoplasms (CPNs) are an increasingly diagnosed entity. Their heterogeneity poses complex diagnostic and management challenges. Despite frequently encountering these entities, particularly in the context of the increased imaging of patients in modern medicine, doctors have to rely on incomplete and ambiguous published literature. The aim of this project was to review the guidelines relating to CPNs using evidence-based practice (EBP) methods.

METHODS

A search of both the primary and secondary literature was performed. Five sets of guidelines were identified which were then methodologically appraised by the AGREE II instrument, a validated and widely utilised tool for guideline development assessment.

RESULTS

The 2014 'Italian consensus guidelines for the diagnostic work-up and follow-up of cystic pancreatic neoplasms' were found to be the most methodologically sound guidelines, on the basis of both the overall score and average weighted domain score.

CONCLUSIONS

The current best guidelines were identified. The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument can be used for retrospective review of published guidelines or as a roadmap for guideline-writing groups. All guidelines found were methodologically limited. Further longitudinal/prospective studies are required to improve the level of evidence.

KEY POINTS

• Cystic pancreatic neoplasms (CPNs) are an increasingly encountered entity in modern medicine. • Clinical uncertainty remains with regard to optimal diagnostic and management strategies. • The Italian consensus guidelines for cystic pancreatic neoplasms are currently the best guidelines.

Parenchyma-Sparing, Limited Pancreatic Head Resection for Benign Tumors and Low-Risk Periampullary Cancer--a Systematic Review

BACKGROUND

Parenchyma-sparing local extirpation of benign tumors of the pancreatic head provides the potential benefits of preservation of functional tissue and low postoperative morbidity.

METHODS

Medline/PubMed, Embase, and Cochrane library databases were surveyed for studies performing limited resection of the pancreatic head and resection of a segment of the duodenum and common bile duct or preservation of the duodenum and common bile duct (CBD). The systematic analysis included 27 cohort studies that reported on limited pancreatic head resections for benign tumors. In a subgroup analysis, 12 of the cohort studies were additionally evaluated to compare the postoperative morbidity after total head resection including duodenal segment resection (DPPHR-S) and total head resection conserving duodenum and CBD (DPPHR-T).

RESULTS

Three hundred thirty-nine of a total of 503 patients (67.4%) underwent total head resections. One hundred forty-seven patients (29.2%) of them underwent segmental resection of the duodenum and CBD (DPPHR-S) and 192 patients (38.2%) underwent preservation of duodenum and CBD. One hundred sixty-four patients experienced partial head resection (32.6%). The final histological diagnosis revealed in 338 of 503 patients (67.2%) cystic neoplasms, 53 patients (10.3%) neuroendocrine tumors, and 20 patients (4.0%) low-risk periampullary carcinomas. Severe postoperative complications occurred in 62 of 490 patients (12.7%), pancreatic fistula B + C in 40 of 295 patients (13.6%), resurgery was experienced in 2.7%, and delayed gastric emptying in 12.3%. The 90-day mortality was 0.4%. The subgroup analysis comparing 143 DPPHR-S patients with 95 DPPHR-T patients showed that the respective rates of procedure-related biliary complications were 0.7% (1 of 143 patients) versus 8.4% (8 of 95 patients) (p ≤ 0.0032), and rates of duodenal complications were 0 versus 6.3% (6 of 95 patients) (p ≤ 0.0037). DPPHR-S was associated with a higher rate of delay of gastric emptying compared to DPPHR-T (18.9 vs. 2.1%, p ≤ 0.0001).

CONCLUSION

Parenchyma-sparing, limited head resection for benign tumors preserves functional pancreatic and duodenal tissue and carries in terms of fistula B + C rate, resurgery, rehospitalization, and 90-day mortality a low risk of postoperative complications. A subgroup analysis exhibited after total pancreatic head resection that preserves the duodenum and CBD an association with a significant increase in procedure-related biliary and duodenal complications compared to total head resection combined with resection of the periampullary segment of the duodenum and resection of the intrapancreatic CBD.

Suboptimal accuracy of carcinoembryonic antigen in differentiation of mucinous and nonmucinous pancreatic cysts: results of a large multicenter study

BACKGROUND AND AIMS

The exact cutoff value at which pancreatic cyst fluid carcinoembryonic antigen (CEA) level distinguishes pancreatic mucinous cystic neoplasms (MCNs) from pancreatic nonmucinous cystic neoplasms (NMCNs) is unclear. The aim of this multicenter retrospective study was to evaluate the diagnostic accuracy of cyst fluid CEA levels in differentiating between MCNs and NMCNs.

METHODS

Consecutive patients who underwent EUS with FNA at 3 tertiary care centers were identified. Patients with histologic confirmation of cyst type based on surgical specimens served as the criterion standard for this analysis. Demographic characteristics, EUS morphology, FNA fluid, and cytology results were recorded. Multivariate logistic regression analysis to identify predictors of MCNs was performed. Receiver-operating characteristic (ROC) curves were generated for CEA levels.

RESULTS

A total of 226 patients underwent surgery (mean age, 61 years, 96% white patients, 39% female patients) of whom 88% underwent Whipple's procedure or distal pancreatectomy. Based on surgical histopathology, there were 150 MCNs and 76 NMCNs cases. The median CEA level was 165 ng/mL. The area under the ROC curve for CEA levels in differentiating between MCNs and NMCNs was 0.77 (95% confidence interval, 0.71-0.84, P < .01) with a cutoff of 105 ng/mL, demonstrating a sensitivity and specificity of 70% and 63%, respectively. The cutoff value of 192 ng/mL yielded a sensitivity of 61% and a specificity of 77% and would misdiagnose 39% of MCN cases.

CONCLUSIONS

Cyst fluid CEA levels have a clinically suboptimal accuracy level in differentiating MCNs from NMCNs. Future studies should focus on novel cyst fluid markers to improve risk stratification of pancreatic cystic neoplasms.

Delayed Growth in Incidental Pancreatic Cysts: Are the Current American College of Radiology Recommendations for Follow-up Appropriate?

PURPOSE

To evaluate growth kinetics of asymptomatic small (<2 cm) incidental pancreatic cysts and to assess potential implications of these in the context of current American College of Radiology recommendations.

MATERIALS AND METHODS

This institutional review board-approved HIPAA-compliant retrospective study with waiver of informed consent included patients with asymptomatic small incidental pancreatic cysts (diameter, 5-20 mm) with two or more magnetic resonance (MR) examinations performed at least 6 months apart at a tertiary institution. The largest cyst dimension was measured on T2-weighted single-shot fast spin-echo images by one of six radiologists (1-3 years of experience) who were trained to measure pancreatic cysts in a similar manner. All analysis was conducted at the patient level by choosing the cyst that exhibited the greatest growth over the follow-up period in each patient. Fisher exact, χ(2), and Kruskal-Wallis tests and analysis of variance were used to test correlation between cyst characteristics and growth.

RESULTS

A total of 259 patients (mean age, 65 years ± 11 [standard deviation], male-to-female ratio, 42:58) with 370 asymptomatic small incidental pancreatic cysts were included. At presentation, median cyst size was 9.4 mm (interquartile range [IQR], 7.0-12.2 mm), and 64 patients (25%; 95% confidence interval [CI]: 20, 30) had septations. The median imaging follow-up period was 2.2 years (IQR, 1.2-3.9 years; range, 0.5-11.0 years), with a median of three MR examinations (IQR, two to four examinations) per patient. In 171 (66%; 95% CI: 60, 72) of the 259 patients, cysts remained stable; in 18 (7%; 95% CI: 4, 11), cysts shrank; and in 70 (27%; 95% CI: 22, 33), cysts grew (median total growth and median annual growth of 4.8 mm and 2.3 mm/y, respectively). Age, cyst size, and cyst septation at presentation were not predictive of growth. Overall, 29 (11%), 16 (6%), and four (1.5%) of the cysts increased in size after 1, 2, and 3 years of initial stability, respectively. Of the 18 patients who underwent pancreatic surgery, only one patient with an intraductal papillary mucinous neoplasm had high-grade dysplasia. One patient developed pancreatic adenocarcinoma remotely at the location of the pancreatic cyst diagnosed 11 months prior.

CONCLUSION

In the majority of patients, asymptomatic small incidental pancreatic cysts remained stable during a median follow-up period of 2.2 years; however, in 27% of patients, cysts increased in size over time, with 11% growing after an initial 1-year period of stability. Current American College of Radiology recommendations to discontinue imaging follow-up after 1 year of stability may need to be reevaluated.

Discovery and Validation of Biomarkers That Distinguish Mucinous and Nonmucinous Pancreatic Cysts

The use of advanced imaging technologies for the identification of pancreatic cysts has become widespread. However, accurate differential diagnosis between mucinous cysts (MC) and nonmucinous cysts (NMC) consisting of pseudocysts (NMC1) and nonmucinous neoplastic cysts (NMC2) remains a challenge. Thus, it is necessary to develop novel biomarkers for the differential diagnosis of pancreatic cysts. An integrated proteomics approach yielded differentially expressed proteins in MC that were verified subsequently in 99 pancreatic cysts (21 NMC1, 41 NMC2, and 37 MC) using a method termed GeLC-stable isotope dilution-multiple reaction monitoring-mass spectrometry (GeLC-SID-MRM-MS) along with established immunoassay techniques. We identified 223 proteins by nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC/MS-MS). Nine candidate biomarkers were identified, including polymeric immunoglobulin receptor (PIGR), lipocalin 2 (LCN2), Fc fragment of IgG-binding protein (FCGBP), lithostathine-1-alpha (REG1A), afamin (AFM), chymotrypsin C (caldecrin; CTRC), amylase, alpha 2B (pancreatic; AMY2B), lectin, galactoside-binding, soluble, 3 binding protein (LGALS3BP), and chymotrypsin-like elastase family, member 3A (CELA3A), which were established as biomarker candidates for MC. In particular, we have shown that a biomarker subset, including AFM, REG1A, PIGR, and LCN2, could differentiate MC not only from NMC (including NMC1) but also from NMC2. Overall, the MS-based comprehensive proteomics approach used in this study established a novel set of candidate biomarkers that address a gap in efforts to distinguish early pancreatic lesions at a time when more successful therapeutic interventions may be possible.

Accuracy of 18F-FDG PET/CT, Multidetector CT, and MR Imaging in the Diagnosis of Pancreatic Cysts: A Prospective Single-Center Study

Accurate diagnosis of the nature of pancreatic cysts is challenging but more important than ever, in part because of the increasing number of incidental cystic findings in the pancreas. Preliminary data suggest that (18)F-FDG PET/CT may have a significant influence on clinical decision making, although its role is still evolving. Our aim was to prospectively compare the accuracy of combined (18)F-FDG PET and contrast-enhanced CT ((18)F-FDG PET/CT), multidetector CT (MDCT), and MR imaging in differentiating malignant from benign pancreatic cysts.

METHODS

Thirty-one consecutive patients with pancreatic cysts were enrolled in the study. They underwent a protocol including (18)F-FDG PET/CT, MDCT, and MR imaging combined with MR cholangiopancreatography, all of which were evaluated in a masked manner. The findings were confirmed macroscopically at surgery or histopathologic analysis (n = 22) or at follow-up (n = 9).

RESULTS

Of the 31 patients, 6 had malignant and 25 had benign lesions. The diagnostic accuracy was 94% for (18)F-FDG PET/CT, compared with 77% and 87% for MDCT (P < 0.05) and MR imaging, respectively. (18)F-FDG PET/CT had a negative predictive value of 100% and a positive predictive value of 75% for pancreatic cysts. The maximum standardized uptake value was significantly higher in malignant (7.4 ± 2.6) than in benign lesions (2.4 ± 0.8) (P < 0.05). When the maximum standardized uptake value was set at 3.6, the sensitivity and specificity were 100% and 88%, respectively. Furthermore, when compared with MDCT and MR imaging, respectively, (18)F-FDG PET/CT altered the clinical management of 5 and 3 patients, respectively.

CONCLUSION

(18)F-FDG PET/CT is an accurate imaging modality for differentiating between benign and malignant pancreatic cysts. We recommend the use of (18)F-FDG PET/CT in the evaluation of diagnostically challenging pancreatic cysts.

Estimation of the prevalence of asymptomatic pancreatic cysts in the population of San Marino

BACKGROUND

There has been a dramatic increase in the number of pancreatic cystic lesions observed in the past two decades but data regarding the prevalence of cysts in the general population are lacking.

METHODS

All the individuals who undergo CT at the San Marino State Hospital are residents of the Republic of San Marino; their demographic distribution is available and precise. CT scans carried out over 1 year at the State Hospital were reviewed for asymptomatic pancreatic cysts.

RESULTS

1061 relevant CT scans were carried out on 814 patients; 762 individuals were eligible for the study and 650 patients underwent contrast-enhanced CT. Thirty-five patients had at least one cyst at contrast-enhanced CT (5.4%). The prevalence of cysts increased with increasing age up to 13.4% (95% CI 6.6-20) in individuals 80-89 years of age (p < .001). Cyst prevalence was significantly higher in patients who underwent CT for malignancy (p = .038) but this difference was no longer significant in multivariate analysis. The odds of a cyst being present increased by 1.05 (95% CI 1.02-1.09) for each increasing year of age (p = .002). Approximately a quarter of the patients with cysts died within 1 year after CT from non pancreas-related disease. The estimated standardized age-adjusted cyst prevalence is 2194 per 100,000 people.

CONCLUSIONS

The likelihood of having a pancreatic cyst correlates with increasing age, not with the presence of extra-pancreatic malignancies. The estimated prevalence of CT-detectable asymptomatic pancreatic cysts in the general population is 2.2%.

Implications of imaging criteria for the management and treatment of intraductal papillary mucinous neoplasms - benign versus malignant findings

OBJECTIVES

Evaluation of computed tomography (CT) and magnetic resonance imaging (MRI) for differentiation of pancreatic intraductal papillary mucinous neoplasm (IPMN) subtypes based on objective imaging criteria.

METHODS

Fifty-eight patients with 60 histologically confirmed IPMNs were included in this retrospective study. Eighty-three imaging studies (CT,n = 42; MRI,n = 41) were analysed by three independent blinded observers (O1-O3), using established imaging criteria to assess likelihood of malignancy (-5, very likely benign; 5, very likely malignant) and histological subtype (i.e., low-grade (LGD), moderate-grade (MGD), high-grade dysplasia (HGD), early invasive carcinoma (IPMC), solid carcinoma (CA) arising from IPMN).

RESULTS

Forty-one benign (LGD IPMN,n = 20; MGD IPMN,n = 21) and 19 malignant (HGD IPMN,n = 3; IPMC,n = 6; solid CA,n = 10) IPMNs located in the main duct (n = 6), branch duct (n = 37), or both (n = 17) were evaluated. Overall accuracy of differentiation between benign and malignant IPMNs was 86/92 % (CT/MRI). Exclusion of overtly malignant cases (solid CA) resulted in overall accuracy of 83/90 % (CT/MRI). The presence of mural nodules and ductal lesion size ≥30 mm were significant indicators of malignancy (p = 0.02 and p < 0.001, respectively).

CONCLUSIONS

Invasive IPMN can be identified with high confidence and sensitivity using CT and MRI. The diagnostic problem that remains is the accurate radiological differentiation of premalignant and non-invasive subtypes.

KEY POINTS

• CT and MRI can differentiate benign from malignant forms of IPMN. • Identifying (pre)malignant histological IPMN subtypes by CT and MRI is difficult. • Overall, diagnostic performance with MRI was slightly (not significantly) superior to CT.

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.

Early detection and prevention of pancreatic cancer: Is it really possible today?

Pancreatic cancer is the 4^th leading cause of cancer-related death in Western countries. Considering the low incidence of pancreatic cancer, population-based screening is not feasible. However, the existence of a group of individuals with an increased risk to develop pancreatic cancer has been well established. In particular, individuals suffering from a somatic or genetic condition associated with an increased relative risk of more than 5- to 10-fold seem to be suitable for enrollment in a surveillance program for prevention or early detection of pancreatic cancer. The aim of such a program is to reduce pancreatic cancer mortality through early or preemptive surgery. Considering the risk associated with pancreatic surgery, the concept of preemptive surgery cannot consist of a prophylactic removal of the pancreas in high-risk healthy individuals, but must instead aim at treating precancerous lesions such as intraductal papillary mucinous neoplasms or pancreatic intraepithelial neoplasms, or early cancer. Currently, results from clinical trials do not convincingly demonstrate the efficacy of this approach in terms of identification of precancerous lesions, nor do they define the outcome of the surgical treatment of these lesions. For this reason, surveillance programs for individuals at risk of pancreatic cancer are thus far generally limited to the setting of a clinical trial. However, the acquisition of a deeper understanding of this complex area, together with the increasing request for screening and treatment by individuals at risk, will usher pancreatologists into a new era of preemptive pancreatic surgery. Along with the growing demand to treat individuals with precancerous lesions, the need for low-risk investigation, low-morbidity operation and a minimally invasive approach becomes increasingly pressing. All of these considerations are reasons for preemptive pancreatic surgery programs to be undertaken in specialized centers only.

Endoscopic ultrasound in the diagnosis of pancreatic intraductal papillary mucinous neoplasms

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

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Single-center retrospective study of prospectively collected data.

SETTINGS

Tertiary referral center.

PATIENTS AND INTERVENTIONS

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

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

Incidental pancreatic cysts: natural history and diagnostic accuracy of a limited serial pancreatic cyst MRI protocol

OBJECTIVES

To examine the natural history of incidentally detected pancreatic cysts and whether a simplified MRI protocol without gadolinium is adequate for lesion follow-up.

METHODS

Over a 10-year period, 301-patients with asymptomatic pancreatic cysts underwent follow-up (45 months ± 30). The magnetic resonance imaging (MRI) protocol included axial, coronal T2-weighted images, MR cholangiopancreatographic and fat suppressed T1-weighted sequences before and after gadolinium. Three radiologists independently reviewed the initial MRI, the follow-up studies using first only unenhanced images, then secondly gadolinium-enhanced-sequences. Lesion changes during follow-up were recorded and the added value of gadolinium-enhanced sequences was determined by classifying the lesions into risk categories.

RESULTS

Three hundred and one patients (1,174 cysts) constituted the study population. Only 35/301 patients (12 %) showed significant lesion change on follow-up. Using multivariate analysis the only independent factor of lesion growth (OR = 2.4; 95 % CI, 1.7-3.3; P < 0.001) and mural nodule development (OR = 1.9; 95 % CI, 1.1-3.4, P = 0.03) during follow-up was initial lesion size. No patient with a lesion initial size less than 2 cm developed cancer during follow-up. Intra-observer agreement with and without gadolinium enhancement ranged from 0.86 to 0.97. After consensus review of discordant cases, gadolinium-enhanced sequences demonstrated no added value.

CONCLUSION

Most incidental pancreatic cystic lesions did not demonstrate change during follow-up. The addition of gadolinium-enhanced-sequences had no added-value for risk assignment on serial follow-up.

KEY POINTS

Significant growth of pancreatic cysts occurred in a minority of patients only. No lesion <2 cm demonstrated any change during the first year of follow-up. Intra-observer agreement between MR pancreatic protocols with and without gadolinium was excellent. Gadolinium application had limited value for follow-up of asymptomatic pancreatic cystic lesions.

European experts consensus statement on cystic tumours of the pancreas

Cystic lesions of the pancreas are increasingly recognized. While some lesions show benign behaviour (serous cystic neoplasm), others have an unequivocal malignant potential (mucinous cystic neoplasm, branch- and main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm). European expert pancreatologists provide updated recommendations: diagnostic computerized tomography and/or magnetic resonance imaging are indicated in all patients with cystic lesion of the pancreas. Endoscopic ultrasound with cyst fluid analysis may be used but there is no evidence to suggest this as a routine diagnostic method. The role of pancreatoscopy remains to be established. Resection should be considered in all symptomatic lesions, in mucinous cystic neoplasm, main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm as well as in branch duct intraductal papillary mucinous neoplasm with mural nodules, dilated main pancreatic duct >6mm and possibly if rapidly increasing in size. An oncological partial resection should be performed in main duct intraductal papillary mucinous neoplasm and in lesions with a suspicion of malignancy, otherwise organ preserving procedures may be considered. Frozen section of the transection margin in intraductal papillary mucinous neoplasm is suggested. Follow up after resection is recommended for intraductal papillary mucinous neoplasm, solid pseudo-papillary neoplasm and invasive cancer.

Pancreatic cysts: a systematic approach and second look

BACKGROUND

Pancreatic cysts are relatively rare, but constitute an important disease entity that poses a challenge with clinical, radiological, and pathological differential diagnosis.

METHODS

New attention has been drawn to pancreatic cysts given their potential cure rates with resection. However, preoperative distinction between neoplastic and benign lesions needs further study for effective strategies in identification and management. The role and safety of cystic fluid analysis remains to be clarified in this context.

RESULTS

The presence of mural nodules is a significant indicator for malignancy; however, size as a reliable predictor remains controversial. Specific criteria are required with particular focus on the histologic subtype of pancreatic lesions.

CONCLUSION

We review recent developments in the understanding and management of cystic lesions of the pancreas.

Natural history of asymptomatic pancreatic cystic neoplasms

BACKGROUND

The management of asymptomatic pancreatic cysts is controversial and indications for excision are based on pathology and natural history.

OBJECTIVES

This study aimed to examine outcomes of asymptomatic lesions using a protocol based on size and cyst fluid analysis.

METHODS

Asymptomatic cysts were identified from a prospectively maintained database. Sequential cross-sectional imaging studies were assessed, and results of endoscopic ultrasound-guided aspiration were co-analysed.

RESULTS

A total of 338 asymptomatic patients underwent evaluation. Overall, 84 cysts were <1.5 cm and 254 were ≥1.5 cm in diameter. Median patient follow-up was 5.1 years [interquartile range (IQR): 4.1-6.9 years]. In the group in which cysts measured <1.5 cm in diameter, median cyst size was 1.0 cm (IQR: 0.6-1.2 cm) at presentation and increased to 1.2 cm (IQR: 0.7-1.6 cm) during follow-up. Five (6.0%) patients underwent resection, all within 2 months of presentation. In the group in which cysts measured ≥1.5 cm in diameter, median cyst size was 2.5 cm (IQR: 2.0-3.4 cm) at presentation and increased to 2.7 cm (IQR: 3.0-4.2 cm). A total of 63 (24.8%) patients underwent resection. Surgery was performed with 2 months in 53 (84.1%) patients, within 12 months in four (6.3%) patients and at >12 months post-presentation in six (9.5%) patients. A total of 70.6% of resected specimens were identified as malignancies or mucinous lesions.

CONCLUSIONS

Asymptomatic cysts of <1.5 cm in diameter can safely be followed by imaging and are expected to undergo little change. A quarter of all asymptomatic cysts measuring ≥1.5 cm are appropriately resected based on imaging and cyst fluid analysis.

Advances in the diagnosis of cystic neoplasms of the pancreas

PURPOSE OF REVIEW

Management of pancreatic cystic neoplasms is challenging due to limitations of current diagnostic tests. There is considerable interest in developing an accurate and cost-effective diagnostic test (or panel of tests) to differentiate cyst types and to identify those which would benefit most from surgical resection.

RECENT FINDINGS

Current multidetector computed tomography scans may have improved accuracy to distinguish between mucinous and nonmucinous cysts. Attempts to generate quantitative criteria from cross-sectional imaging to differentiate cyst types have yielded mixed results. DNA mutations and microRNA show promise in the ability to distinguish between mucinous and nonmucinous cysts. Cyst fluid mucin glycoproteins and cytokines may identify those cysts with high malignant potential. Proteomic analysis may yield other biomarker candidates.

SUMMARY

Analysis of DNA mutations and proteins within pancreatic cyst fluid have identified potential biomarkers to aid with the management of patients with pancreatic cystic neoplasms.

[Radiological evaluation of intraductal papillary mucinous neoplasm]

The intraductal papillary mucinous neoplasm (IPMN) is the most frequent cystic neoplasm of the pancreas. Due to the widespread use of cross-sectional imaging IPMN is being incidentally recognized with increasing frequency. The most common type is branch- duct IPMN which occurs multifocally in about 20-30%. Patients with IPMN may present with symptoms resembling chronic pancreatitis and episodes of acute pancreatitis are increasingly being reported which usually have a mild course. The most important diagnostic technique is contrast-enhanced multidetector computed tomography (MDCT), which most frequently allows the differentiation from other cystic lesions and enables the attribution to branch duct or main duct IPMN. Magnetic resonance imaging (MRI) in combination with magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound are superior in depicting the fine architecture of cystic tumors. Particularly for evaluation of malignant transformation and extent of malignant disease, high resolution imaging is essential. Whereas main duct IPMN is an indication for resection therapy for small and asymptomatic branch duct IPMN periodic surveillance at 6-12 month intervals is recommended.

Pancreatic incidentalomas

Pancreatic incidentalomas are defined as asymptomatic pancreatic lesions, discovered incidentally by imaging for an unrelated indication. They are being discovered with increasing frequency as the use of high quality cross sectional imaging is becoming more widespread. These lesions cover a wide spectrum of pathology from benign simple cysts through potentially malignant lesions such as intraductal papillary mucinous neoplasia, to frankly malignant adenocarcinoma. In this article we outline the incidence, imaging characteristics and natural history of the various incidental lesions with emphasis to neuroendocrine tumors. A diagnostic approach is also suggested, including the rational use of further imaging, serum biochemistry and the utility of ultrasound guided aspiration of cyst fluid if present. We examine several proposed classification systems and discuss the role of surgery, surveillance and prognosis.

The use of protein-based biomarkers for the diagnosis of cystic tumors of the pancreas

Proteomics is a powerful method used to identify, characterize, and quantify proteins within biologic samples. Pancreatic cystic neoplasms are a common clinical entity and represent a diagnostic and management challenge due to difficulties in accurately diagnosing cystic lesions with malignant potential and assessing the risk of malignant degeneration. Currently, cytology and other biomarkers in cyst fluid have had limited success in accurately distinguishing both the type of cystic neoplasm and the presence of malignancy. Emerging data suggests that the use of protein-based biomarkers may have greater utility in helping clinicians correctly diagnose the type of cyst and to identify which cystic neoplasms are malignant. Several candidate proteins have been identified within pancreatic cystic neoplasms as potential biomarkers. Future studies will be needed to validate these findings and move these biomarkers into the clinical setting.

Imaging in staging and management of pancreatic ductal adenocarcinoma

Pancreatic cancer is a relatively common malignancy of the gastrointestinal tract for which complete surgical excision remains the only curative option. Being infiltrative in nature and bearing a complex anatomical relationship with various organs, peritoneal ligaments and vascular structures, accurate anatomical staging is key in treatment of these patients. In this article, we will discuss and provide a brief overview of anatomy and use of imaging in staging pancreatic cancer.