Clinical management of intraductal papillary mucinous tumors of the pancreas based on imaging findings

Systematic review on surveillance for non-resected branch-duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

The management of branch-duct type intraductal papillary mucinous neoplasms (BD-IPMN) varies in existing guidelines. This study investigated the optimal surveillance protocol and safe discontinuation of surveillance considering natural history in non-resected IPMN, by systematically reviewing the published literature.

METHODS

This review was guided by PRISMA. Research questions were framed in PICO format "CQ1-1: Is size criteria helpful to determine surveillance period? CQ1-2: How often should surveillance be carried out? CQ1-3: When should surveillance be discontinued? CQ1-4: Is nomogram predicting malignancy useful during surveillance?". PubMed was searched from January-April 2022.

RESULTS

The search generated 2373 citations. After screening, 83 articles were included. Among them, 33 studies were identified for CQ1-1, 19 for CQ1-2, 26 for CQ1-3 and 12 for CQ1-4. Cysts <1.5 or 2 cm without worrisome features (WF) were described as more indolent, and most studies advised an initial period of surveillance. The median growth rate of cysts <2 cm ranged from 0.23 to 0.6 mm/year. Patients with cysts <2 cm showing no morphological changes and no WF after 5-years of surveillance have minimal malignancy risk of 0-2%. Two nomograms created with over 1000 patients had AUCs of around 0.8 and appear to be feasible in a real-world practice.

CONCLUSIONS

For patients with suspected BD-IPMN <2 cm and no other WF, less frequent surveillance is recommended. Surveillance may be discontinued for cysts that remain stable during 5-year surveillance, with consideration of patient condition and life expectancy. With this updated surveillance strategy, patients with non-worrisome BD-IPMN should expect more streamlined management and decreased healthcare utilization.

Imaging Features for Predicting High-Grade Dysplasia or Malignancy in Branch Duct Type Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Systematic Review and Meta-Analysis

BACKGROUND

The consensus guidelines for branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas are mostly based on imaging features. This study aimed to determine imaging features and their diagnostic accuracy for predicting high-grade dysplasia (HGD)/malignancy in BD-IPMN, including mixed type.

METHODS

The PubMed, Embase, and Cochrane databases were searched, and data were extracted from relevant studies. As the main diagnostic accuracy index, diagnostic odds ratios (DORs) of imaging features for diagnosing HGD/malignancy in BD-IPMNs were pooled using the random-effects model. A bivariate random-effects approach was used to construct summary receiver operating characteristic curves for sensitivity and specificity estimation.

RESULTS

The pooled DOR was the highest for the enhanced solid component/mural nodule (MN) (DOR, 12.21; 95 % confidence interval [CI], 6.14-24.27), followed by a main pancreatic duct (MPD) diameter of 10 mm or greater (DOR, 7.93; 95 % CI, 3.02-20.83), solid component (DOR, 4.85; 95 % CI, 2.49-9.42), lymphadenopathy (DOR, 4.84; 95 % CI, 1.11-21.06), MN (DOR, 4.48; 95 % CI, 3.15-6.39), an MPD diameter of 5 mm or greater (DOR, 3.69; 95 % CI, 2.62-5.19), abrupt change in MPD caliber with distal pancreatic atrophy (DOR, 2.65; 95 % CI, 1.66-4.24), thickened/enhancing walls (DOR, 2.38; 95 % CI, 1.57-3.60), and cyst size of 3 cm or larger (DOR, 1.98; 95 % CI, 1.48-2.64). The largest area under the curve (0.89 and 0.95, respectively) and high specificity (0.95 and 0.98, respectively) also were found for enhanced solid component/MN and an MPD diameter of 10 mm or greater, albeit with low sensitivity (0.38 and 0.14, respectively).

CONCLUSIONS

The aforementioned imaging features could aid in predicting HGD/malignancy of BD-IPMN. Furthermore, enhanced solid component/MN and an MPD diameter of 10 mm or greater were the most important predictors of HGD/malignancy in BD-IPMN and should be considered as indications for surgery.

MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY (MRCP) VERSUS ENDOSONOGRAPHY-GUIDED FINE NEEDLE ASPIRATION (EUS-FNA) FOR DIAGNOSIS AND FOLLOW-UP OF PANCREATIC INTRADUCTAL PAPILLARY MUCINOUS NEOPLASMS

Background:

Intraductal papillary mucinous tumor (IPMN) are being diagnosed with increasing frequency. Computerized tomography scanning is commonly used as the primary imaging modality before surgery nonetheless magnetic resonance cholangiopancreatography (MRCP) provides better characterization. Endosonography-guided fine needle aspiration (EUS-FNA) has emerged as a way to reach pathological diagnose.

Aim:

To compare results of both methods with surgical pathology findings for classification of IPMN.

Methods:

Thirty-six patients submitted to surgical resection with preoperative suspect of IPMN were submitted preoperatively to MRCP and EUS-FNA. Images obtained were analyzed according to a classification determined for each method. ROC curve was used for statistical analysis, that compared the images tests with the purpose of finding the best method for diagnosis and classification of IPMN.

Results:

Sixteen patients underwent pancreatoduodenectomy, 16 to subtotal pancreatectomy and only four laparotomy. Pathological diagnosis was IPMN (n=33) and pancreatic intraepithelial neoplasia type 2 (n=3). Twenty-nine revealed non-invasive neoplasia and invasive form in four patients. MRCP and EUS-FNA have correctly diagnosed and classified (type of IPMN), in 62.5% and 83.3% (p=0.811), the affected segment location in 69% and 92% (p=0.638) and identification of nodules and/or vegetation presence in 45% and 90% (p=0.5). Regarding to histopathological diagnosis by EUS-FNA the sensitivity was 83.3%; specificity was 100%; positive predictive value was 100%; negative predictive value was 33.3% and accuracy was 91.7%.

Conclusions:

There was no significant difference in the diagnosis of IPMN. However, EUS-FNA showed better absolute results than MRCP to identify nodule and/or vegetation.

Predictors of Malignancy in "Pure" Branch-Duct Intraductal Papillary Mucinous Neoplasm of the Pancreas without Enhancing Mural Nodules on CT Imaging: A Nationwide Multicenter Study

Background/Aims

Presence of enhanced mural nodules, which can be visualized using computed tomography (CT), is one of high-risk stigmata in branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs). Conversely, the absence of enhanced mural nodules on preoperative imaging does not exclude malignant risk. The present study aimed to investigate other morphological features as predictors of malignancy in "pure" BD-IPMNs without enhanced mural nodules on CT.

Methods

This retrospective study included 180 patients with surgically confirmed "pure" BD-IPMNs of the pancreas and no enhanced mural nodules on preoperative CT. The study was conducted at 15 tertiary referral centers throughout South Korea. Univariate and multivariate analyses were used to identify significant predictors of malignancy.

Results

BD-IPMNs with low-grade (n=84) or moderate-grade (n=76) dysplasia were classified as benign; those with high-grade dysplasia (n=8) or invasive carcinoma (n=12) were classified as malignant. The multivariate analysis revealed that cyst size ≥30 mm (odds ratio, 8.6; p=0.001) and main pancreatic duct diameter ≥5 mm (odds ratio, 4.1; p=0.01) were independent risk factors for malignancy in "pure" BD-IPMNs without enhanced mural nodules on CT. Endoscopic ultrasound detected enhanced mural nodules (6/82) that had been missed on CT, and two IPMNs with enhanced mural nodules were malignant.

Conclusions

In patients with "pure" BD-IPMNs who have no enhanced mural nodules on CT, cyst size ≥30 mm and main pancreatic duct diameter ≥5 mm may be associated with malignancy.

Risk Factors for Malignancy of Branch-Duct Intraductal Papillary Mucinous Neoplasms: A Critical Evaluation of the Fukuoka Guidelines With a Systematic Review and Meta-analysis

OBJECTIVES

This study aimed to evaluate the accuracy of the risk factors proposed by Fukuoka guidelines in detecting malignancy of branch-duct intraductal papillary mucinous neoplasms.

METHOD

Diagnostic meta-analysis of cohort studies. A systematic literature search was conducted using MEDLINE, the Cochrane Library, Scopus, and the ISI-Web of Science databases to identify all studies published up to 2014.

RESULTS

Twenty-five studies (2025 patients) were suitable for the meta-analysis. The "high risk stigmata" showed the highest pooled diagnostic odds ratio (jaundice, 6.3; positive citology, 5.5; mural nodules, 4.8) together with 2 "worrisome features" (thickened/enhancing walls, 4.2; duct dilatation, 4.0) and 1 "other parameters" (carbohydrate antigen 19-9 serum levels, 4.6).

CONCLUSIONS

An "ideal risk factor" capable of recognizing all malignant branch-duct intraductal papillary mucinous neoplasms was not identified and some "dismal areas" remain. However, "high risk stigmata" were strongly related to malignancy, mainly enhancing mural nodules. Among the "worrisome features," duct dilatation and thickened/enhancing walls were underestimated, and their diagnostic performance was similar to those of "high risk stigmata." The carbohydrate antigen 19-9 serum level should be added to the Fukuoka algorithm because this value could help in carrying out correct management.

Risk of pancreatic malignancy and mortality in branch-duct IPMNs undergoing surveillance: A systematic review and meta-analysis

BACKGROUND

Safety of non-operative management for low-risk branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) is debated.

AIM

To perform a systematic review/meta-analysis to determine their risk of developing pancreatic malignancy and of pancreatic malignancy-related deaths.

METHODS

A MEDLINE search was performed and methodology was based on PRISMA statement. Incidence rates of overall pancreatic malignancy, malignant BD-IPMN, IPMN-distinct PDAC, and of pancreatic malignancy-related death rates were calculated by dividing the total number of events by the total number of person-years (pyrs) of follow-up. Heterogeneity was determined by I(2) statistic.

RESULTS

20 studies including 2177 patients were included. Mean follow-up ranged from 29.3 to 76.7 months. Overall, 82 patients (3.7%) developed a pancreatic malignancy with a pooled estimate rate of 0.007/pyrs (I(2)=32.8%). The pooled estimate rate of malignant IPMN was 0.004/pyrs (I(2)=40.8%), and the pooled estimate rate of distinct PDAC 0.002/pyrs (I(2)=0%). The rate of death due to pancreatic malignancy during follow-up was 0.9%, with an overall pooled estimate rate of death of 0.002/pyrs (I(2)=0%).

CONCLUSION

Non-operative management of low-risk BD-IPMN is safe, with a very low risk of malignant transformation of IPMN and of distinct PDAC. The rate of pancreatic malignancy-related mortality is low, particularly when compared with the mortality of pancreatic surgery.

Natural history of branch duct intraductal papillary mucinous neoplasm with mural nodules: a Japan Pancreas Society multicenter study

OBJECTIVE

This study aimed to elucidate the natural history of intraductal papillary mucinous neoplasm (IPMN) of the pancreas with mural nodules (MNs) in branch duct IPMN (BD-IPMN).

METHODS

Among the 402 registered patients with BD-IPMN on long-term follow-up at 10 institutions in Japan, 53 patients with MNs of less than 10 mm in height detected by endosonography were included in this study. The morphological changes of the BD-IPMN in these patients and histologic findings of the resected specimen were investigated.

RESULTS

The median height of the MNs at the initial diagnosis was 3 mm (range, 1-8 mm), and 12 (23%) of the 53 patients showed an increase in the height of the MNs during follow-up (mean duration, 42 months). Six patients underwent surgery because of an increase in the height of MNs, yielding high-grade dysplasia in 1 patient and low-grade dysplasia in 5 patients. No patients developed invasive carcinoma derived from IPMN, and distinct pancreatic ductal adenocarcinoma developed in 1 (2%) patient. The incidence of the development of malignancy in BD-IPMNs, including distinct pancreatic ductal adenocarcinoma, was similar to that of those without MNs.

CONCLUSIONS

In patients who have BD-IPMN with MNs of less than 10 mm in height, observation instead of immediate resection is considered to be possible.

Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis

OBJECTIVE

To systematically determine the imaging findings for distinguishing malignant and benign branch-duct type intraductal papillary mucinous neoplasms (BD-IPMNs), including mixed type, and their diagnostic value through meta-analysis of published studies.

BACKGROUND

Management of BD-IPMNs, including mixed type, largely relies on imaging findings. The current knowledge on imaging findings to distinguish malignant and benign BD-IPMNs has weak evidence and is mostly from scattered individual retrospective studies.

METHODS

Thorough literature search in Ovid-MEDLINE and EMBASE databases was conducted to identify studies where findings of computed tomography, magnetic resonance imaging, and endoscopic ultrasonography of BD-IPMNs with or without main pancreatic duct (MPD) dilatation were correlated with surgical/pathological findings. Review of 1128 article candidates, including full-text review of 102 articles, identified 23 eligible articles with a total of 1373 patients for meta-analysis. Dichotomous data regarding distinction between malignant and benign BD-IPMNs were pooled using random effects model to obtain the diagnostic odds ratios (DORs) and their 95% confidence intervals (CIs) of various individual imaging findings for diagnosing malignant BD-IPMN.

RESULTS

Presence of mural nodules revealed the highest pooled DOR (95% CI) of 6.0 (4.1-8.8) followed by MPD dilatation [3.4 (2.3-5.2)], thick septum/wall [unadjusted, 3.3 (1.5-6.9); publication bias-adjusted, 2.3 (0.9-5.5)], and cyst size greater than 3 cm [2.3 (1.5-3.5)]. Multilocularity and multiplicity of the cystic lesions did not reveal statistically significant association with malignancy.

CONCLUSIONS

Presence of mural nodules should be regarded highly suspicious for malignancy warranting a surgical excision whereas cyst size greater than 3 cm, MPD dilatation (5-9 mm), or thick septum/wall may better be managed by careful observation and/or further evaluation.

Cyst features and risk of malignancy in intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis

BACKGROUND & AIMS

International guidelines for the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas recommend surgical resection of those with specific characteristics. We performed a meta-analysis to evaluate the risk of malignancy associated with each of these features of IPMNs.

METHODS

We performed a comprehensive search of MEDLINE from January 1, 1996, to November 11, 2011, for studies that included any of the features mentioned in the consensus guidelines for surgical resection of main duct and branch duct IPMNs. Data were analyzed from 41 studies for the following features: cyst size greater than 3 cm, the presence of mural nodules, dilated main pancreatic duct, symptoms, and main duct vs branch duct IPMNs. Malignant IPMNs were defined as those with carcinoma in situ or more advanced histology. A separate meta-analysis was performed for each risk factor to calculate pooled odds ratios (ORs). A random-effects model was used, based on the assumption of variation among study populations.

RESULTS

The risks of malignancy associated with individual cyst features were as follows: cyst size greater than 3 cm (OR, 62.4; 95% confidence interval [CI], 30.8-126.3), presence of a mural nodule (OR, 9.3; 95% CI, 5.3-16.1), dilatation of the main pancreatic duct (OR, 7.27; 95% CI, 3.0-17.4), and main vs branch duct IPMN (OR, 4.7; 95% CI, 3.3-6.9). There was a moderate level of heterogeneity among studies (I(2) range, 34-67).

CONCLUSIONS

Based on a meta-analysis, cyst features proposed by the international guidelines for resection of IPMN were highly associated with malignancy. However, based on our findings, not all cyst features should be weighted equally when considering risk of malignancy; cyst size greater than 3 cm was associated most strongly with malignant IPMN.

Proper management and follow-up strategy of branch duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND AND AIM

It has been reported that main duct intraductal papillary mucinous neoplasms are more invasive and have a worse prognosis than branch duct intraductal papillary mucinous neoplasms. Therefore, an aggressive surgical approach has mainly been recommended for all MD-IPMNs. However, the surgical management of BD-IPMNs has been controversial and the consensus guidelines are not specific for an indicator of malignancy in BD-IPMNs. The objective of this study was to determine the proper management and follow-up strategy of BD-IPMNs.

METHODS

We monitored and analysed patients with presumed BD-IPMNs between March 1995 and March 2010.

RESULT

The mean value of the initial cyst size in all patients with BD-IPMNs was 2.19 cm. Amongst 194 patients with BD-IPMNs, 34 underwent immediate surgical resection, 152 were followed conservatively. Amongst the 152 conservatively managed patients, 18 (11.8%) underwent surgical resection after a median follow-up of 12.7 months (range, 3-48 months). In 132 patients who were managed conservatively without surgery, the mean incremental rate of cyst size growth was 0.0038 cm/month during a median of 30.7 months of follow-up and there were no IPMN-related deaths.

CONCLUSION

Amongst patients with BD-IPMNs, about 10% have surgery within approximately 1 year from the time of diagnosis because of the occurrence of new malignant stigmata. Therefore, a conservative approach without surgery and careful follow-up every 3 months or 6 months during the first year after diagnosis can be safely advocated in patients with BD-IPMNs larger than 10mm in size who have no risk factors for malignant IPMNs.

Current status on the diagnosis and management of pancreatic cysts in the Asia-Pacific region: role of endoscopic ultrasound

Endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) play increasingly prominent roles in the diagnosis and management of pancreatic cysts. The Asian Consortium of Endoscopic Ultrasound was recently formed to conduct collaborative research in this area. This is a review of literature on true pancreatic cysts. Due to the lack of systematic studies, there are no robust data on the true incidence of pancreatic cystic lesions in Asia and any change in over the recent decades. Certain EUS morphological features have been used to predict particular types of pancreatic cysts. Pancreatic cyst fluid viscosity, cytology, pancreatic enzymes, and tumor markers, in particular carcinoembryonic antigen, can aid in the diagnosis of pancreatic cysts. Hemorrhage and infection are the most common complications of EUS-FNA of pancreatic cysts. Pancreatic cysts can either be observed or resected depending on the benign or malignant nature, or malignant potential of the lesions. Guidelines from an international consensus did not require positive cytological findings to be present in their recommendation for resection, which included all mucinous cystic neoplasms, all main-duct intraductal papillary mucinous neoplasms (IPMN), all mixed IPMN, symptomatic side-branch IPMN, and side-branch IPMN larger than 3 cm. In patients with poor surgical risks, EUS-guided cyst ablation of mucinous pancreatic cysts is an alternative. As long-term prospective data on pancreatic cysts are still not available in Asia, management strategies are largely based on risk stratification by surgical risk and malignant potential. Gene expression profiling of pancreatic cyst fluid and confocal laser endomicroscopic examination of pancreatic cysts are novel techniques currently being studied.

Noninvasive intraductal papillary mucinous neoplasm with para-aortic lymph node metastasis: report of a case

Intraductal papillary mucinous neoplasms (IPMNs) with an invasive carcinoma component are categorized as minimally invasive or invasive. The prognosis after resection of minimally invasive IPMNs has been reported to be similar to that after resection of noninvasive IPMNs. We report a case of noninvasive branchduct IPMN with multiple lymph node metastases, including para-aortic node involvement, treated successfully by distal pancreatectomy with lymph node dissection. The patient, a 72-year-old man, had two multilocular cysts in the pancreatic body, 22 mm and 14 mm in diameter, respectively, communicating with the main pancreatic duct. The primary tumor and nodal metastases had similar patterns of mucin expression. The primary tumor contained a region of carcinoma in situ (CIS) without histological evidence of stromal invasion; thus, it was diagnosed as minimally invasive carcinoma. We report this case to emphasize two important points: first, even small branch-duct IPMNs without any indications for resection can have a component of CIS or more advanced disease; and second, even branch-duct IPMNs without any apparent invasive component can be aggressive and spread to the lymph nodes. Therefore, nodal status should be assessed carefully in every patient, even if the primary IPMN is not advanced.

Natural history of intraductal papillary mucinous neoplasia: How much do we really know?

Information on the natural history of intraductal papillary mucinous neoplasia (IPMN) is currently inadequate due to a lack of carefully orchestrated long-term follow-up on a large cohort of patients with asymptomatic disease. Based on the available data, one can draw the conclusions that main duct IPMN is commonly associated with malignancy and an aggressive operative stance should be taken with resection being offered to most patients who are suitable operative candidates. In contrast, the majority of branch type IPMN with a diameter of less than 3 cm can be safely followed with routine surveillance imaging provided they lack the high-risk covariates of age, symptomatology, nodularity or wall thickness.

Single-pattern convergence of K-ras mutation correlates with surgical indication of intraductal papillary mucinous neoplasms

OBJECTIVES

One or more patterns of 6 K-ras mutations are detected in cells from the pancreatic juice of patients with intraductal papillary mucinous neoplasms (IPMNs). We investigated whether these mutations are associated with malignant progression.

METHODS

Between January 2002 and December 2007, 53 patients with IPMN were subjected to collection of pure pancreatic juice to evaluate K-ras mutation. According to the histological and radiological findings, the IPMNs were classified into 4 groups: carcinoma group, adenoma group, high-risk group, and low-risk group. We retrospectively investigated the mutation with these groups.

RESULTS

In patients with a positive K-ras mutation, a single pattern of K-ras mutation was observed in 80% (8/10) of the carcinoma group, in 71% (5/7) of the adenoma group, in 40% (2/5) of the high-risk group, and in 38% (8/21) of the low-risk group. The rate of a single pattern of K-ras mutation decreased in a stepwise order (P = 0.017). The incidence of a single pattern of K-ras mutation was significantly higher in the patients who received surgical therapy (75%, 12/16) than in those who did not (38%, 10/26; P = 0.033).

CONCLUSIONS

The present study suggests that the single-clonal convergence of K-ras mutation is associated with the malignant progression of IPMNs.

Metachronous intraductal papillary mucinous neoplasm with carcinoma in situ of the pancreas arising within a short interval: report of a case

A 61-year-old man with an intraductal papillary mucinous neoplasm (IPMN) and carcinoma in situ (CIS) of the pancreatic body initially underwent a distal pancreatectomy. Postoperative follow-up included computed tomography (CT) and ultrasonography (US) every 6 months. Intraductal papillary mucinous neoplasm of the pancreatic head was diagnosed 17 months later using peroral pancreatoscopy (POPS) including a biopsy, revealing IPMN with highly dysplastic changes. A total pancreatectomy was therefore performed. The pathological examination revealed IPMN with CIS. The patient was discharged from the hospital and is doing well as of 1 year postoperatively. Although cautious surveillance seems mandatory, consensus has not yet been reached regarding postoperative surveillance. This report presents an unreported case of metachronously arising IPMN with CIS within a relatively early interval, thus suggesting that surveillance every 6 months is preferable to > or = 1 year. In addition, endoscopic US, endoscopic retrograde cholangiopancreatography, intraductal US, or POPS should be included in pathological examinations to avoid missing opportunities to treat lesions such as noninvasive IPMN with a good prognosis. Surgically indicated patients with noninvasive recurrence should therefore be strongly considered to undergo a total pancreatectomy.

Cyst size indicates malignant transformation in branch duct intraductal papillary mucinous neoplasm of the pancreas without mural nodules

OBJECTIVES

In branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas, the importance of the cyst size to predict malignancy is still controversial. Our aim was to elucidate the malignant potential of branch duct IPMN without mural nodules (flat branch duct IPMN).

METHODS

Seventy-three patients with flat branch duct IPMNs were studied in our institution.

RESULTS

There were 6 malignant IPMNs in this series, all of which were 30 mm or more in size, whereas there was no malignancy in IPMNs of less than 30 mm. Statistically significant predictors of malignancy were atypical cytological condition and main pancreatic duct (MPD) diameter of 5 mm or more. The cyst size of 30 mm or more tended to be associated with malignancy. The frequency of malignancy in flat branch duct IPMNs with the size of 30 mm or more and MPD diameter of less than 5 mm was 3.6%, whereas there were 5 malignant cases (26.3%) in flat branch duct IPMNs with the size of 30 mm or more and MPD diameter of 5 mm or more.

CONCLUSIONS

We conclude that the size criteria (> or =30 mm) to predict malignancy proposed in the international consensus guidelines is appropriate and resection or meticulous follow-up using cytological examination and MPD dilatation is needed in patients with flat branch duct IPMNs.

Intraductal papillary mucinous neoplasms of the pancreas: differentiation of malignant and benign tumors by endoscopic ultrasound findings of mural nodules

BACKGROUND AND AIM

Intraductal papillary mucinous neoplasms (IPMNs)have a wide pathologic spectrum and it is difficult to differentiate malignant from benign tumors. The aim of this study was to identify predictors of malignancy using contrast-enhanced endoscopic ultrasound (CE-EUS).

SUBJECTS AND METHODS

In our institute, main duct type and mixed type IPMNs, branch duct type IPMNs with mural nodules, and IPMNs with coexistent invasive ductal cancer were indications for surgery. Eighty-seven IPMNs (14 main duct, 25 mixed, and 48 branch duct type) were resected and CE-EUS findings were compared with pathologic findings. Twelve clinicopathological variables and CE-EUS morphologic findings were assessed.Mural nodules defined as blood flow supplied protrusions were classified into 4 types: type I: low papillary nodule, type II: polypoid nodule, type III:papillary nodule, and type IV: invasive nodule.

RESULTS

Forty-two, 26, 16, and 3 were pathologically diagnosed as adenoma,noninvasive carcinoma, invasive IPMNs, and coexistent invasive ductal cancer, respectively. Multivariable logistic regression analysis showed that types III/IV mural nodule (odds ratio = 10.8; 95% confidential intervals = 2.75-56.1) and symptomatic IPMNs (odds ratio = 4.31; 95% confidential intervals = 1.37-14.7) were significant for malignancy. For mural nodule diameter, invasive IPMNs were significantly larger, but types III and IV mural nodules were more frequently associated with malignancy, particularly invasive cancer, at 88.9% and 91.7%, respectively. The diagnosis of IPMNs with types III or IV mural nodule as malignant resulted in a sensitivity of 60%, specificity of 92.9%, and accuracy of 75.9%.

CONCLUSIONS

In conclusion, new morphologic criteria were useful to identify the malignant potentials of IPMNs.

Single-institution validation of the international consensus guidelines for treatment of branch duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

The international consensus guidelines (the guidelines) for management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas recommend surgical resection of branch duct IPMNs with any of the following features: cyst size >30 mm, mural nodules, main pancreatic duct diameter >6 mm, positive cytology, and symptoms. The aim of this study was to evaluate the usefulness of these guidelines for resection of branch duct IPMNs.

METHODS

We reviewed 84 consecutive patients with branch duct IPMNs who underwent surgical resection at our hospital between January 1984 and December 2007.

RESULTS

Sixty-nine patients had indications for resection according to the guidelines. Malignant IPMNs had significantly larger cysts than benign tumors (P = 0.026). Patients with malignant IPMNs had significantly more indications for resection than those with benign IPMNs (2.6 +/- 1.0 vs. 1.7 +/- 0.9, P < 0.001), and 36 of the 37 patients with malignant IPMNs had indications. The sensitivity of the guidelines for predicting malignancy was 97.3%. One of 15 patients without indications had malignancy, and the specificity was low (29.8%).

CONCLUSIONS

The guidelines show a high sensitivity for predicting malignancy of branch duct IPMNs, but the specificity is low. The cyst size and the total number of indications in each patient should be taken into account when predicting the risk of malignancy for branch duct IPMNs.

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

BACKGROUND

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

OBJECTIVE

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

PATIENTS

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

DESIGN

Single-center retrospective study.

SETTING

Academic medical center.

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

Single-center and small number of patients.

CONCLUSIONS

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

Multifocal intraductal papillary mucinous neoplasm of the pancreas-A case report

Cystic neoplasms of the pancreas are relatively rare, comprising 10 percent of pancreatic cysts and only 1 percent of pancreatic cancers. Cystic neoplasms include mucinous cystic neoplasms, serous cystadenomas, papillary cystic tumors, cystic islet cell tumors and intraductal papillary mucinous neoplasms of the pancreas (IPMNs). IPMN was first described in 1982. It has been most commonly described in 60 to 70 years old males, and represents a relatively “new” but increasingly recognized disease. The improvement and widespread use of modern imaging equipments and heightened awareness of physicians contribute to the increasing incidence of IPMN. The majority of IPMNs are located in the pancreatic head (75%) while the rest involves the body/tail regions. Multifocal IPMNs have been hypothesized, but the true presence of multifocality is unknown. Here we present a 72-year-old male diagnosed with IPMN (carcinoma in situ) in the pancreatic head and a branch duct type IPMN (duct atypia) in the pancreatic body and tail. The patient underwent a Whipple intervention and a distal pancreatectomy. A three-year disease-free survival has been observed so far.

Evaluation of serial changes of pancreatic branch duct intraductal papillary mucinous neoplasms by follow-up with magnetic resonance imaging

The purpose of this study was to clarify the biological behaviour of branch duct type intraductal papillary mucinous neoplasm (IPMN) by evaluating serial changes at magnetic resonance cholangiopancreatography (MRCP). Fifty-two patients with a diagnosis of branch duct IPMN based on either endoscopic retrograde cholangiopancreatography (ERCP) (9/52) and/or MRCP examination (43/52), were followed up over a mean period of 31.2 months (range 12-108). All imaging data were retrospectively reviewed by two radiologists in order to evaluate serial changes in the maximum diameter of the cystic lesion, in the presence of main pancreatic duct dilatation (MPD), and filling defects within the lesion. Statistical analysis was performed using the Fisher exact probability test. Serial MRCP proved growth in seven cases. In two cases the size decreased; in the remaining 43 there was no change in size. Lesions greater than 3 cm at presentation and the presence of MPD dilatation or filling defects at imaging were most likely to grow. Only 2/37 cystic lesions less than 3 cm in diameter grew in size over the period of observation. No cystic lesion showed changes in morphology and structure. Branch duct IPMNs smaller than 3 cm, without associated filling defects, tend to be stable, making 'watch and wait' management possible.

Ultrasonographic findings and natural history of intraductal papillary-mucinous neoplasms of the pancreas

It is clear that the prevalence of malignancy is high in the main-duct type of intraductal papillary-mucinous neoplasm (IPMN). Branch-duct IPMNs include several histologic conditions such as carcinoma, adenoma, and hyperplasia. Intraductal papillary adenocarcinoma and papillary adenoma are characterized by papillary protrusions and thick septum-like structures in dilated ducts as delineated by ultrasonography. A solid mass showing a mixedecho pattern in the pancreatic parenchyma is a characteristic finding of invasive types of IPMN. The international guidelines for the management of branch-duct IPMNs suggest that the appearance of symptoms attributable to the cyst, the presence of intramural nodules, a cyst size greater than 30 mm, and dilation of the main pancreatic duct (>6 mm) are indications for resection. Based on the relationship between the height of a papillary protrusion and the diameter of a cystic dilated branch as well as on histological findings, branch-duct IPMNs with papillary protrusions more than 10 mm in height as shown by imaging should be resected, and it is not adequate to differentiate carcinoma from other lesions based on the diameter of cystic branches alone. A follow-up study on branch-duct IPMNs revealed that most papillary protrusions showed a slow increase in size or development of lateral spread, and that there was no development of cancer with stromal invasion during an average follow-up of 46 months. Therefore, the presence of intramural nodules alone should not be an indication for surgery. Also, patients without papillary protrusions or thick septum-like structures are not immediate candidates for surgery. Invasive adenocarcinoma can develop at a pancreatic site different from the area of interest showing cystic changes, with such invasion possibly being multicentric. Therefore, in patients with branch-duct IPMNs, attention should be paid to the entire pancreas when performing follow-up examinations.

Intraductal papillary mucinous neoplasm of the pancreas: assessment of the likelihood of invasiveness with multisection CT

PURPOSE

To evaluate the capabilities of multisection computed tomography (CT) in determining the likelihood of invasiveness of intraductal papillary mucinous neoplasm (IPMN).

MATERIALS AND METHODS

The institutional review board approved this research and waived informed consent from the patients. Two radiologists blinded to the pathologic assessment of malignancy or parenchymal invasion of IPMN retrospectively evaluated CT images of 61 consecutive surgically resected tumors (26 adenomas, 15 noninvasive carcinomas, and 20 invasive carcinomas) in patients who underwent multiphase contrast material-enhanced CT with 0.5- or 1-mm collimation. The findings were statistically analyzed by using univariate and multivariate analyses, with the optimal cutoff levels of each continuous parameter determined by generating receiver operating characteristic curves.

RESULTS

The following findings showed significant differences among the three groups: maximum diameter of the main pancreatic duct (MPD), size (length of major axis) of the largest mural nodule in the MPD or in any associated cystic lesion, abnormal attenuating area in the surrounding parenchyma, calcification in the lesion, protrusion of the MPD into the ampulla of Vater, and bile duct dilatation. An MPD diameter of 6 mm or larger, a mural nodule of 3 mm or larger, and an abnormal attenuating area were independently predictive of malignancy. A mural nodule of 6.3 mm or larger in the MPD and an abnormal attenuating area were independently predictive of parenchymal invasion. According to these criteria, the sensitivity, specificity, and accuracy for identifying malignancy were 83%, 81%, and 82% and for identifying parenchymal invasion were 90%, 88%, and 89%, respectively.

CONCLUSION

Multisection CT is useful for distinguishing among adenoma, noninvasive carcinoma, and invasive carcinoma in patients with IPMN.

MR imaging and MR cholangiopancreatography of multifocal intraductal papillary mucinous neoplasms of the side branches: MR pattern and its evolution

PURPOSE

This paper describes the magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) pattern of multifocal intraductal papillary mucinous tumours (IPMT) of the pancreatic side branches and its evolution during followup.

MATERIALS AND METHODS

Twenty-six patients with multifocal IPMT of the side branches were included in this retrospective study. Inclusion criteria were > or =2 ectasic side branches, presence of communication with the main pancreatic duct, and > or =2 MRI/MRCP examinations after > or = 6-12 months. Exclusion criteria were IPMT involving both the main pancreatic duct and its branch ducts, previous surgery and lack of follow-up MRI examinations. Median follow-up was 27 (range 6-59) months. Images were assessed qualitatively and quantitatively. Qualitative assessment considered: the number of cystic lesions of the branch ducts, morphology of the communication between the cystic lesion and the main duct (direct or neck), presence of intraluminal filling defects within the cystic lesions, presence of mural nodules and mural enhancement of the cystic lesion. quantitative assessment considered mean maximal diameter of the cystic lesions and mean length of the communication neck.

RESULTS

At diagnosis, the mean number of cystic lesions of the side branches was 7.5. a communication neck was detected in 16/26 patients (60%). Intraluminal filling defects in the side branches were present in 6/26 patients (23%). Mural nodules were seen in 1/26 patients (4%). The mean diameter of the cystic lesions was 18.8 mm. The mean length of the communication neck was 6.9 mm. At follow-up, the mean number of cystic lesions of the side branches was 8.4. A communication neck was detected in 20/26 patients (77%). Intraluminal filling defects in the side branches were detected in 7/26 patients (27%); mural nodules were seen in 2/26 patients (8%). Mural enhancement of the branch duct was detected in 2/26 patients (8%). The mean diameter of the cystic lesions increased to 22.3 mm (p < 0.05), and the mean length of the communication neck was 8.6 mm.

CONCLUSIONS

MultifocaL IPMT of the side branches shows a constant but very slow progression over time. In our series, only 2/26 patients showed mural nodules.

Natural history of intraductal papillary mucinous neoplasms (IPMN): current evidence and implications for management

Intraductal papillary mucinous neoplasms (IPMNs) show varying degrees of dysplasia throughout the neoplasm that can range from adenoma to invasive carcinoma, with dysplastic changes of borderline neoplasms and carcinoma in situ in between. An understanding of the natural history, and especially the required time to transform into either carcinoma in situ or an invasive adenocarcinoma, is critically important for management policy. This topic serves as the rationale for the present analysis. At the beginning of February 2007, using the key word "IPMN" in PubMed, we initially selected 119 publications using the principal criteria as defined by the WHO classification. We identified 20 appropriate original reports and one consensus paper. Neither randomized control trials (RCT) or systematic reviews of RCTs (level 1 evidence) nor cohort studies or reviews of cohort studies (level 2 evidence) have been published. Only one report fit the criteria for level 3 evidence (case control study). Nineteen papers satisfied criteria for level 4 (cases series) and two for level 5 (expert opinion publication). After additional review and analysis, we considered only six reports to be "cornerstone papers" of merit for the final review. Clues to the natural history of IPMNs can be gained by using several methods to examine the articles: (a) to verify different prognoses between main and side branch duct subtypes; (b) to compare the average age of patients with benign vs. malignant IPMNs; (c) to summarize the findings of nonoperative, observational studies based on follow up by clinical, biochemical, and imaging techniques without operative resection; (d) to determine the prognostic importance of the status of the resection margin; and (e) to follow patients clinically after surgical resection. Although important aspects of the natural history of IPMN are still unknown, the following conclusions can be drawn: (1) Branch-duct IPMNs are less aggressive than main-duct IPMNs. (2) Malignancy is more common in older patients. (3) Malignancy (invasive or carcinoma in situ) is found in about 70% of resected main-duct IPMNs. (4) After resection of noninvasive IPMNs (branch- and main-duct varieties), recurrence is rare (<8%). (5) After resection of invasive IPMN, recurrence occurs in 50-65% of patients.

CT vs MRCP: optimal classification of IPMN type and extent

INTRODUCTION

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are being diagnosed with increased frequency. CT scanning commonly serves as the primary imaging modality before surgery. We hypothesized MRCP provides better characterization of IPMN type/extent, which more closely matches actual pathology.

METHODS

Of 214 patients treated with IPMN (1991-2006), 30 had both preoperative CT and MRCP. Of these, 18 met imaging study criteria. Independent readers performed retrospective, blinded analyses using standardized criteria for IPMN type and extent.

RESULTS

A ductal connection was detected on 73% of MRCP scans and only 18% of CT. IPMN type was classified differently in seven (39%); four (22%) of which were read on CT as having main duct involvement where this was not appreciated on MRCP or found on surgical pathology. MRCP showed multifocal disease in 13(72%) versus only 9(50%) on CT. A different disease distribution was seen in 9(50%). Finally, 101 branch lesions were identified on MRCP compared to 46 on CT.

CONCLUSIONS

CT falls short of MRCP in detecting a ductal connection, estimating main duct involvement, and identification of small branch duct cysts. These factors influence diagnostic accuracy, cancer risk stratification and operative strategy. MRCP should be employed for optimal management of patients with IPMN.

Collateral branches IPMTs: secretin-enhanced MRCP

Recently, the fantastic evolution of imaging modalities (especially MR, MDCT, EUS) has raised many issues regarding the correct classification of smaller and smaller lesions, their preoperative evaluations, and indications of most appropriate treatment. However, it is still debated which technique should be employed for the diagnosis and the follow-up of intraductal papillary mucinous tumours (IPMTs). Despite the superb spatial resolution of MDCT, nowadays most of the authors agree on considering MR with magnetic resonance cholangiopancreatography (MRCP) the imaging modality of choice in studying IPMTs. In particular, MRCP is rapid, non-invasive, and accurate in detecting, localizing, and correctly classifying IPMT. The diagnostic performance of MRCP is even improved after the introduction of secretin stimulation. In fact, dynamic MRCP studies after secretin administration, besides facilitating the depiction of the structural characteristics of the lesions, make easier the detection of the communicating duct of branch duct IPMTs with the main pancreatic duct, especially if the newest high resolution 3D heavily T2-weighted sequences are utilized. Secretin stimulation is also useful in the demonstration of early changes of associated chronic pancreatitis. Consequently, we believe that secretin-enhanced MRCP is the most suitable imaging modality in the diagnosis and follow-up of IPMTs of the collateral branches.

Intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND/AIMS

Intraductal papillary mucinous neoplasms (IPMNs) are neoplasms of the pancreatic duct epithelium characterized by intraductal papillary growth and thick mucin secretion. Quantities of mucin fill the main and/or branches of pancreatic ducts and cause ductal dilatation. This review encompasses IPMNs, including symptoms, diagnosis, management, and prognosis.

METHODS

A Pubmed database search was performed. All abstracts were reviewed and all articles in which cases of IPMNs could be identified were further scrutinized. Further references were extracted by cross-referencing.

RESULTS

Only one-third of all patients are symptomatic. According to the site of involvement, IPMNs are classified into three types: main duct type, branch duct type, and combined type. Most branch type IPMNs are benign, while the other two types are frequently malignant. The presence of large mural nodules increases the possibility of malignancy in all types. Presence of a large branch type IPMN and marked dilatation of the main duct indicate the existence of adenoma at least. Synchronous or metachronous malignancies may be developed in various organs. Endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, and intraductal ultrasonography clearly demonstrate ductal dilatation and mural nodules, while magnetic resonance pancreatography best visualizes the entire outline of IPMNs.

CONCLUSIONS

Prognosis is excellent after complete resection of benign and non-invasive malignant IPMNs. The extent of pancreatic resection and the intraoperative management of resection margins remain controversial. Total pancreatectomy should be reserved for patients with resectable but extensive IPMNs involving the whole pancreas; its benefits, however, must be balanced against operative and postoperative risks. Regular monitoring for disease recurrence is important after surgery.

Invasive carcinomas derived from intraductal papillary mucinous neoplasms of the pancreas: a long-term follow-up assessment with CT imaging

OBJECTIVE

To describe computed tomography (CT) findings of invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs) of the pancreas during long-term follow-up.

METHODS

Follow-up CT findings of 5 patients with IPMNs progressing to invasive carcinomas were respectively reviewed for 12 to 63 months. All patients underwent thin-section 3-phase helical and/or multislice CT.

RESULTS

Invasive carcinomas were detected as hypo- (n = 3) or hyperattenuating (n = 2) solid masses in the pancreatic parenchyma on contrast-enhanced CT. Hypoattenuating masses were mostly visualized on arterial dominant phase images. In 4 branch-duct type IPMNs, the solid masses appeared with (n = 3) or without (n = 1) dilatation of the main pancreatic duct after 3 to 5 years. In the remaining combined-type IPMN, a solid mass was detected on initial CT and progressively increased during the follow-up.

CONCLUSIONS

Arterial dominant phase CT is useful for detecting invasive carcinoma derived from IPMNs and is an effective follow-up method.

Cystic tumors of the pancreas

Cystic tumors of the pancreas are less frequent than solid lesions and are often detected incidentally, as many of these lesions are small and asymptomatic. However, they may be associated with pancreatitis or have malignant potential. With advancements in diagnostic imaging, cystic lesions of the pancreas are being detected with increasing frequency. Many lesions can cause a pancreatic cyst, most being non-neoplastic while approximately 10% are cystic tumors, ranging from benign to highly malignant tumors. With increasing experience it is becoming clear that the prevalence of pseudocyst among cystic lesions of the pancreas is lower than usually presumed. A presumptive diagnosis of pseudocyst based on imaging appearance alone can cause a diagnostic error, and neoplastic cysts of the pancreas are particularly susceptible to this misdiagnosis, which can result in inappropriate treatment. Cystic tumors of the pancreas are formed by serous or mucinous structures showing all stages of cellular differentiation. According to the WHO classification, they can be subdivided on the basis of their histological type and biological behavior into benign tumors, borderline tumors, and malignant tumors. Cystic pancreatic tumors can be subdivided into peripheral (serous cystadenomas, mucinous cystic tumors, solid and papillary epithelial neoplasms, cystic islet cell tumors), which do not communicate with the main pancreatic duct, and ductal tumors (mucinous tumor), according to their site of origin. On the basis of imaging criteria alone, it can be very difficult to differentiate non-tumoral cystic lesions from neoplastic ones. The management of these patients is complex, and it is important to correlate imaging findings with knowledge of the patient’s symptoms and of the natural history and predictors of malignancy in pancreatic cysts.

International consensus guidelines for management of intraductal papillary mucinous neoplasms and mucinous cystic neoplasms of the pancreas

Non-inflammatory cystic lesions of the pancreas are increasingly recognized. Two distinct entities have been defined, i.e., intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). Ovarian-type stroma has been proposed as a requisite to distinguish MCN from IPMN. Some other distinct features to characterize IPMN and MCN have been identified, but there remain ambiguities between the two diseases. In view of the increasing frequency with which these neoplasms are being diagnosed worldwide, it would be helpful for physicians managing patients with cystic neoplasms of the pancreas to have guidelines for the diagnosis and treatment of IPMN and MCN. The proposed guidelines represent a consensus of the working group of the International Association of Pancreatology.

Intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a new pathological entity. It is diagnosed with increasing frequency. However, its natural history and management are still not well defined.

METHODS

A Medline search was undertaken to identify articles using the keywords "intraductal papillary mucinous neoplasms of pancreas", "pancreatic neoplasms", and "pancreatic cyst". Additional papers were identified by a manual search of the references from the key articles.

RESULTS

Surgical resection is the only treatment which can produce a cure. The reported overall 5-year survival for IPMN after surgical resection varies from 36% to 77%; for non-invasive IPMN, 77% to 100% and for invasive IPMN, 27% to 60%. The overall recurrence rate was 7% to 43%. IPMN can recur either as disseminated disease or as isolated pancreatic remnant recurrence even after surgical resection with negative margins.

CONCLUSIONS

Based on the available evidence, patients with IPMN should undergo complete surgical resection. The extent of pancreatic resection and the intra-operative management of resection margins remain controversial. Balancing the risk of recurrence and the morbidity of total pancreatectomy, routine total pancreatectomy for IPMN is not recommended. Total pancreatectomy should only be reserved for patients with resectable but extensive IPMN which involves the whole pancreas. Regular monitoring for disease recurrence is important after surgery as there is a risk of recurrence in both non-invasive and invasive IPMN, and repeat resection for an isolated recurrence in the pancreatic remnant gives good results.

Branch duct-type intraductal papillary mucinous tumor: diagnostic value of multiplanar reformatted images in multislice CT

The object of this study was to evaluate the usefulness of high-resolution multiplanar reformatted (MPR) images obtained by multislice CT in demonstrating connection between pancreatic cystic lesions and the main pancreatic duct. The study included 27 lesions with connection to the main pancreatic duct and 12 lesions without. All but one of the former lesions were branch duct-type intraductal papillary mucinous tumors (IPMTs). Oblique and curved MPR images with 0.5 mm continuous slices were generated from pancreatic-phase axial images reconstructed with 0.5 mm or 1 mm thickness at 0.5 mm intervals over a 260 mm field of view. The diagnostic capabilities for demonstrating connection with the main pancreatic duct were compared among axial images, MPR images, and both axial and MPR images in combination using the Brier score. The diagnosis in MPR images for demonstrating connection was more certain than that in axial images (P<0.05). Compared with MPR images alone, the use of both axial and MPR images resulted in further improvements in diagnostic performance, although the difference was not statistically significant. The use of high-resolution MPR images significantly improves diagnostic performance for demonstrating connection between pancreatic cystic lesions and the main pancreatic duct, which is useful for the diagnosis of branch duct-type IPMT.

Multicenter analysis of clinicopathologic features of intraductal papillary mucinous tumor of the pancreas: is it possible to predict the malignancy before surgery?

BACKGROUND

Despite recently increasing numbers of reports on intraductal papillary mucinous tumors (IPMTs), difficulties still remain in terms of diagnosis, treatment, and prognosis. The purpose of this multicenter study was to evaluate the clinicopathologic features of IPMT in Korea and to suggest predictive criteria for malignancy in IPMT.

METHODS

We retrospectively reviewed the clinicopathologic data of 208 patients who underwent operations for IPMT between 1993 and 2002 at 28 institutes in Korea.

RESULTS

Of the 208 patients (mean age, 61 years), 147 were men and 61 were women. A total of 124 patients underwent pancreatoduodenectomy, 42 underwent distal pancreatectomy, 17 underwent total pancreatectomy, and 25 underwent limited pancreatic resection. There were 128 benign cases (adenoma, n = 62; borderline, n = 66) and 80 malignant cases (noninvasive, n = 29; invasive, n = 51). A significant difference in 5-year survival was observed between the benign and malignant groups (92.6% vs. 65.3%; P = .006). Of the six factors (age, location, duct dilatation, mural nodule, main duct type, and tumor size) that showed statistical differences by univariate analysis between the benign and malignant groups, three were significant by multivariate analysis--namely, mural nodule (P = .009), tumor size (P = .023), and a dilated duct size (P = .010).

CONCLUSIONS

A significant proportion of IPMTs are malignant, although the overall prognosis of IPMT is superior to that of ordinary pancreatic cancer. Radical surgery is recommended for IPMT with the predictors of malignancy: mural nodule, tumor size (> or =30 mm), and dilated duct size (> or =12 mm).

Intraductal Papillary Mucinous Neoplasms of the Pancreas: CT Patterns of Recurrence and Multiobserver Performance in Detecting Recurrent Neoplasm After Surgical Resection

OBJECTIVE

The purposes of our study were to describe the CT appearance of recurrent intraductal papillary mucinous neoplasms of the pancreas after surgical resection and estimate the performance of CT in detecting recurrent neoplasms.

MATERIALS AND METHODS

A single unblinded reviewer characterized the presence and appearance of recurrent intraductal papillary mucinous neoplasms on 66 CT scans of 17 patients with proven recurrence, noting location and appearance of recurrent neoplasm. These results, described in this article, were summarized in tabular format and shown to three blinded observer. The observers then evaluated one postoperative CT examination from every patient at our institution who underwent surgical removal of intraductal papillary mucinous neoplasms (n = 45) for the presence or absence of local or distant recurrence.

RESULTS

The unblinded reviewer found 11 cases of local recurrence. Extrapancreatic local recurrences tend to have solid components (5/6), tend to be located adjacent to the resection margin (5/6), and may exhibit vascular invasion (2/6). Intrapancreatic neoplasms are usually cystic (4/5). Nine patients had distant metastases. Prospective sensitivity for recurrent tumor ranged from 76% (13/17) to 94% (16/17). Sensitivity for local recurrence ranged from 55% (6/11) to 82% (9/11). Specificity ranged from 79% (22/28) to 96% (27/28). Interobserver agreement for predicting recurrence was moderate to substantial (kappa = 0.51-0.65).

CONCLUSION

Locally recurrent intraductal papillary mucinous neoplasms of the pancreas tend to be either extrapancreatic and solid at the resection margin or intrapancreatic and cystic. CT can detect most recurrent intraductal papillary mucinous neoplasms of the pancreas with moderate to substantial interobserver agreement.

Distinguishing benign from malignant intraductal papillary mucinous tumors of the pancreas by imaging techniques

OBJECTIVES

It is often difficult to differentiate benign from malignant intraductal papillary mucinous tumors (IPMTs). This study aimed to differentiate them using various imaging techniques.

METHODS

Receiver operating characteristic curves were used to establish optimal cutoff values to differentiate benign from malignant tumors in 121 patients with histologically confirmed IPMTs.

RESULTS

For branch duct type, accuracy for malignancy was highest using endoscopic ultrasonography (EUS) to measure the cyst diameter, and accuracy was 68.2% at a cutoff value of 33.9 mm. For main duct type, accuracy was highest, 71.1% at a cutoff value of 8.4 mm for main duct diameter, with magnetic resonance cholangiopancreatography. For all imaging techniques and findings, accuracy was highest using EUS, 76.4% at a cutoff value of 5.4 mm for height of protrusion. Each imaging technique had a positive predictive value of 80% if the cut off value for the height of the protruding lesion was met.

CONCLUSIONS

Malignancy can be strongly suspected when the height of protrusion exceeds the respective cutoff values. EUS was most effective to differentiate benign IPMTs from malignant tumors by assessing the height of protrusion.

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.

Natural History of Pancreatic Intraductal Papillary Mucinous Tumor of Branch Duct Type

OBJECTIVE

The purpose of this study was to elucidate the natural history of branch duct type pancreatic intraductal papillary mucinous tumor (IPMT) by evaluating serial changes in the magnetic resonance cholangiopancreatography (MRCP) findings of patients diagnosed with pancreatic IPMT of branch duct type.

METHODS

Thirty-five patients had branch duct type IPMT, including 9 patients with separate lesions, and underwent initial and follow-up MRCP over a period of more than 12 months. The maximum diameter of the cystic lesion, the presence of associated main pancreatic duct (MPD) dilatation, and the presence of a filling defect were evaluated. Serial changes in these findings were analyzed.

RESULTS

Tumor enlargement on follow-up MRCP was observed in 7 cases. Of the 29 branch duct IPMTs without associated MPD dilatation or a filling defect identified on initial MRCP, only 1 showed gradual tumor enlargement. In 4 cases, the cyst size decreased on follow-up MRCP.

CONCLUSIONS

Branch duct type IPMTs grow slowly and can be monitored without operation provided that the tumor shows no associated MPD dilatation or filling defect.

Intraductal papillary mucinous tumors of the pancreas

Cystic neoplasms of the exocrine pancreas are a small fraction of pancreatic tumors. Within that group of cystic neoplasms, intraductal papillary mucinous tumors (IPMTs) can be distinguished from mucinous cystic neoplasms, serous cystic neoplasms, and pseudopapillary cystic tumors. Awareness of IPMTs has increased since the World Health Organization classified these tumors as its own group in 1996. Because of their favorable prognosis, an extensive diagnostic workup for IPMTs should be performed in patients presenting with cystic lesions of the pancreas. This workup often leads to the diagnosis and the predominant tumor location and size, although the extent of the ductal changes can only be established by histopathology. Surgical resection is the therapy of choice for IPMTs. The type of resection depends upon the extent of the quantitative and qualitative ductal involvement. Total pancreatectomy is currently the treatment for an IPMT that comprises the entire main duct.