Intraductal papillary mucinous neoplasms of the pancreas: Correlation of helical CT features with pathologic findings

Dilated common bile duct is commonly associated with main duct Intraductal Papillary Mucinous Neoplasm of the pancreas

BACKGROUND

Dilatation of common bile duct (CBD) is mostly pathological and mainly occurs secondary to mechanical causes. We aimed to explore the prevalence of CBD dilatation in Intraductal Papillary Mucinous Neoplasms of the pancreas (IPMN) among patients referred to EUS.

METHODS

A retrospective study of all patients who had an EUS diagnosis of IPMN from 2011 to 2019 at Galilee Medical Center were extracted. Control group including patients with other types of pancreatic cysts.

RESULTS

Overall, 2400 patients were included in the study, of them 158 patients were diagnosed with pancreatic cysts, 117 patients (74%) diagnosed with IPMN (group A), and 41 patients (26%) diagnosed with other pancreatic cysts (group B). Univariate analysis showed significant association of IPMN (OR 3.8, 95% CI 1.3-11.5), resected gallbladder (GB) (OR 7.75, 95% CI 3.19-18.84), and age (OR 1, 95% CI 1.01-1.08) with CBD dilatation. Classifying IPMN to sub-groups using adjusted multivariate logistic regression analysis, only main duct-IPMN (MD-IPMN) significantly correlated with CBD dilatation compared to branch duct (BD)-IPMN and mixed type-IPMN (OR 19.6, 95% CI 4.57-83.33, OR 16.3, 95% CI 3.02-88.08).

CONCLUSION

MD-IPMN was significantly correlated with dilated CBD. Assessment of the pancreas is warranted in encountered cases of dilated CBD without obvious mechanical cause.

A comparative study between computed tomography and endoscopic ultrasound in the detection of a mural nodule in intraductal papillary mucinous neoplasm -Multicenter observational study in Japan

BACKGROUND/OBJECTIVES

The detection of malignancy is a major concern in the management of intraductal papillary mucinous neoplasm (IPMN). The height of the mural nodule (MN), estimated using endoscopic ultrasound (EUS) and computed tomography (CT), has been considered crucial for predicting malignant IPMN. Currently, whether surveillance using CT or EUS alone is sufficient for detecting MNs remains unclear. This study aimed to compare the ability of CT and EUS to detect MNs in IPMN.

METHODS

This multicenter, retrospective observational study was conducted in 11 Japanese tertiary institutions. Patients who underwent surgical resection of IPMN with MN after CT and EUS examinations were eligible to participate. The MN detection rates between CT and EUS were examined.

RESULTS

Two-hundred-and-forty patients who underwent preoperative EUS and CT had pathologically confirmed MNs. The MN detection rates of EUS and CT were 83% and 53%, respectively (p < 0.001). Additionally, the MN detection rate of EUS was significantly higher than that of CT regardless of morphological type (76% vs. 47% in branch-duct-type IPMN; 90% vs. 54% in mixed IPMN; 98% vs. 56% in main-duct-type IPMN; p < 0.001). Further, pathologically confirmed MNs ≥5 mm were more frequently observed on EUS than on CT (95% vs. 76%, p < 0.001).

CONCLUSIONS

EUS was superior to CT for the detection of MN in IPMN. EUS surveillance is essential for the detection of MNs.

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.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

What Is the Best Way to Identify Malignant Transformation Within Pancreatic IPMN: A Systematic Review and Meta-Analyses

OBJECTIVES

Pancreatic intraductal papillary mucinous neoplasias (IPMNs) represent 25% of all cystic neoplasms and are precursor lesions for pancreatic ductal adenocarcinoma. This study aims to identify the best imaging modality for detecting malignant transformation in IPMN, the sensitivity and specificity of risk features on imaging, and the usefulness of tumor markers in serum and cyst fluid to predict malignancy in IPMN.

METHODS

Databases were searched from November 2006 to March 2014. Pooled sensitivity and specificity of diagnostic techniques/imaging features of suspected malignancy in IPMN using a hierarchical summary receiver operator characteristic (HSROC) approach were performed.

RESULTS

A total of 467 eligible studies were identified, of which 51 studies met the inclusion criteria and 37 of these were incorporated into meta-analyses. The pooled sensitivity and specificity for risk features predictive of malignancy on computed tomography/magnetic resonance imaging were 0.809 and 0.762 respectively, and on positron emission tomography were 0.968 and 0.911. Mural nodule, cyst size, and main pancreatic duct dilation found on imaging had pooled sensitivity for prediction of malignancy of 0.690, 0.682, and 0.614, respectively, and specificity of 0.798, 0.574, and 0.687. Raised serum carbohydrate antigen 19-9 (CA19-9) levels yielded sensitivity of 0.380 and specificity of 0903. Combining parameters yielded a sensitivity of 0.743 and specificity of 0.906.

CONCLUSIONS

PET holds the most promise in identifying malignant transformation within an IPMN. Combining parameters increases sensitivity and specificity; the presence of mural nodule on imaging was the most sensitive whereas raised serum CA19-9 (>37 KU/l) was the most specific feature predictive of malignancy in IPMNs.

Interobserver agreement for detection of malignant features of intraductal papillary mucinous neoplasms of the pancreas on MDCT

OBJECTIVE

The purpose of this retrospective study was to measure interobserver agreement in the assessment of malignant imaging features of intraductal papillary mucinous neoplasms (IPMNs) on MDCT.

MATERIALS AND METHODS

Pancreatic protocol CT studies were reviewed for 84 patients with resected IPMNs. Maximal diameter of the dominant cyst, presence of a mural nodule, presence of a solid component, and diameters of the main pancreatic duct (MPD) and common bile duct (CBD) were measured by four radiologists independently. In each patient, the IPMN was classified into one of three types: main duct, branch duct, or mixed IPMN. Interobserver agreement of lesion features was examined using the intraclass correlation coefficient (ICC) for continuous features and Fleiss kappa for categorical features.

RESULTS

The final dataset included 55 branch duct IPMNs, nine main duct IPMNs, and 20 mixed IPMNs. Moderate agreement (ĸ = 0.458; 95% CI, 0.345-0.564) was observed in assigning branch duct, main duct, or mixed IPMN subtypes. Measurement agreement was substantial to excellent for dominant cyst (ICC = 0.852; 95% CI, 0.777-0.907), MPD (0.753, 0.655-0.837), and CBD (0.608, 0.463-0.724) but only fair to moderate for the detection of the presence of mural nodule (ĸ = 0.284, 0.125-0.432) or solid component (ĸ = 0.405, 0211-0.577).

CONCLUSION

Substantial to excellent interobserver agreement in the measurement of cyst diameter, MPD, and CBD support their use for characterizing malignant features of IPMN on MDCT. However, the subjective interpretation of the presence of solid components and mural nodules by individual radiologists was more variable.

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.

Diagnosis and treatment of cystic pancreatic tumors

Cystic pancreatic tumors (CPTs) have more frequently been identified in the last decade because of increased use of cross-sectional abdominal imaging. Although serous CPTs follow an indolent course and do not necessarily require surgical resection or long-term follow-up, mucinous CPTs (mucinous cystic neoplasms and intraductal papillary mucinous neoplasms) have a greater risk for malignancy. Although most CPTs are initially detected with imaging modalities such as computed tomography or magnetic resonance imaging, these tests alone rarely permit an accurate clinical diagnosis. Endoscopic ultrasound and endoscopic ultrasound-guided, fine-needle aspiration allow real-time examination and biopsy analysis of CPTs, which increases diagnostic accuracy because cytopathology features and tumor markers in cyst fluid can be analyzed. Management of patients with mucinous CPTs by surgery or imaging surveillance is controversial, partially because of limited information about disease progression and the complexities of surgical resection. We review approaches to diagnosis and management of common CPTs.

Mural nodule in branch duct-type intraductal papillary mucinous neoplasms of the pancreas is a marker of malignant transformation and indication for surgery

BACKGROUND

The management of branch duct-type intraductal papillary mucinous neoplasms (IPMNs) remains controversial. This study aimed to elucidate the preoperative clinical factors that identify high-risk malignant transformation in branch duct-type IPMN.

METHODS

We retrospectively evaluated 38 patients diagnosed with branch duct-type IPMN who underwent pancreatectomy, identifying different preoperative factors between adenoma (intraductal papillary mucinous adenoma [IPMA]) and carcinoma (intraductal papillary mucinous carcinoma [IPMC]).

RESULTS

Twelve patients were diagnosed with IPMC. The mean tumor size was 31.9 ± 11.8 mm for IPMA and 35.7 ± 17.1 mm for IPMC (P = .467). No significant differences were found between IPMA and IPMC patients with regard to age, sex, symptoms, and tumor number. The mean diameter of the main pancreatic duct was significantly larger in IPMCs (8.3 ± 5.9 mm) compared with IPMAs (4.7 ± 2.3 mm; P = .011). The mural nodule was a good predictor of malignancy (P = .0002) and was identified as the only independent and significant marker of IPMC in multivariate analysis.

CONCLUSIONS

The presence of mural nodules is a potentially suitable marker for differentiating IPMC from IPMA, and is important for making decisions about surgical interventions.