Podoplanin expression in the cyst wall correlates with the progression of intraductal papillary mucinous neoplasm

Optimization of Endoscopic Ultrasound Characteristics in the Diagnosis of Malignant Intraductal Papillary Mucinous Neoplasm

OBJECTIVES

Endoscopic ultrasound (EUS) is an excellent diagnostic tool that provides high-resolution images of pancreatic cystic lesions. However, its role in the diagnosis of malignant intraductal papillary mucinous neoplasm (IPMN) remains limited and unclear. We aimed to determine the usefulness of this modality for such diagnosis.

METHODS

Overall, 246 patients who underwent EUS for IPMN after computed tomography (CT)/magnetic resonance imaging (MRI) from April 2018 to June 2021 were followed up until March 2022. We assessed the added value of performing EUS after CT or MRI for diagnosing malignant IPMN, using receiver operating characteristic curve analysis. Walls as thick as 2 mm were considered thickened in this study if they were highly uneven.

RESULTS

EUS clearly enhanced accuracy in identifying enhancing nodules and thickened walls. The areas under the receiver operating characteristic curve and corresponding 95% confidence intervals were 0.655 (0.549-0.760) and 0.566 (0.478-0.654) upon CT/MRI but 0.853 (0.763-0.942) and 0.725 (0.634-0.817) when observed using EUS. The combination of nodule size, thickened wall, and main duct size yielded the highest area under the receiver operating characteristic curve (0.944 [0.915-0.973]).

CONCLUSIONS

EUS more accurately detects malignant IPMN, as uneven wall thickening and certain nodules cannot be identified with CT/MRI.

MicroRNAs Deregulated in Intraductal Papillary Mucinous Neoplasm Converge on Actin Cytoskeleton-Related Pathways That Are Maintained in Pancreatic Ductal Adenocarcinoma

Intraductal papillary mucinous neoplasms (IPMN) are pancreatic cystic lesions that can develop into pancreatic ductal adenocarcinoma (PDAC). Although there is an increasing incidence of IPMN diagnosis, the mechanisms of formation and progression into invasive cancer remain unclear. MicroRNAs (miRNAs) are small non-coding RNAs, repressors of mRNA translation, and promising diagnostic biomarkers for IPMN and PDAC. Functional information on the role of early-altered miRNAs in this setting would offer novel strategies for tracking the IPMN-to-PDAC progression. In order to detect mRNAs that are likely to be under miRNA regulation in IPMNs, whole transcriptome and miRNome data from normal pancreatic tissue (n = 3) and IPMN lesions (n = 4) were combined and filtered according to negative correlation and miRNA-target prediction databases by using miRComb R package. Further comparison analysis with PDAC data allowed us to obtain a subset of miRNA-mRNA pairs shared in IPMN and PDAC. Functional enrichment analysis unravelled processes that are mainly related with cell structure, actin cytoskeleton, and metabolism. MiR-181a appeared as a master regulator of these processes. The expression of selected miRNA-mRNA pairs was validated by qRT-PCR in an independent cohort of patients (n = 40), and then analysed in different pancreatic cell lines. Finally, we generated a cellular model of HPDE cells stably overexpressing miR-181a, which showed a significant alteration of actin cytoskeleton structures accompanied by a significant downregulation of EPB41L4B and SEL1L expression. In situ hybridization of miR-181a and immunohistochemistry of EPB41L4B and SEL1L in pancreatic tissues (n = 4 Healthy; n = 3 IPMN; n = 4 PDAC) were also carried out. In this study, we offer insights on the potential implication of miRNA alteration in the regulation of structural and metabolic changes that pancreatic cells experience during IPMN establishment and that are maintained in PDAC.

Usefulness of septal thickness measurement on endoscopic ultrasound as a predictor of malignancy of branched-duct and mixed-type intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND AND AIM

Septal thickness (ST) can predict a malignant branch-duct (BD) and mixed-type intraductal papillary mucinous neoplasm (IPMN) of the pancreas, but its cut-off value has not been established. The aim of the present study was to determine the optimal ST cut-off value to predict malignancy using endoscopic ultrasound (EUS).

METHODS

We retrospectively identified 200 patients with IPMN, including 132 with BD- and mixed-IPMN, who underwent surgical resection between 1989 and 2017. ST was defined as the septum or lesion wall with the maximum diameter in BD- and mixed-IPMN. The possibility of ST as a malignant predictor was examined, as well as the diagnostic ability of ST combined with mural nodule (MN) height for malignant IPMN.

RESULTS

Among the 132 IPMN patients, pathological diagnosis was benign in 81 (61.4%) and malignant in 51 (38.6%). Area under the curve for the diagnosis of malignancy using ST was 0.74 for pathological specimens, 0.70 for EUS and 0.56 for computed tomography. Multivariate analysis showed that the odds ratios for ST ≥2.5 mm and MN height ≥5 mm were 3.51 [95% confidence interval (CI), 1.55-7.97, P = 0.003] and 3.36 (95% CI, 1.52-7.45, P = 0.003), respectively.

CONCLUSIONS

Septal thickness was an independent predictive factor similar to MN height for malignant IPMN in a multivariate analysis. The ST on EUS appeared to be the thickness of a fibrotic septum associated with the malignant transformation of IPMN. An ST cut-off value of 2.5 mm might provide an accurate prediction of malignant IPMN.

Clinical significance of intrapancreatic choledochal cyst excision in surgical management of type I choledochal cyst

Objective To investigate the effectiveness of intrapancreatic choledochal cyst excision in treating type I choledochal cyst, and increase understanding of the need for thorough surgical management of the disease. Methods Primary and secondary (including multiple) surgical cases, treated between 2005 and 2015, were retrospectively analysed, and follow-up data of post-treatment effectiveness to date were reviewed. Differences in curative effects were compared between whole and partial excision of the choledochal cyst. Results Out of 350 cases, patients with whole excision of the choledochal cyst ( n = 272) experienced no associated symptoms in the long-term (3/272 [1.1%] experienced stomach ache or fever). Patients with partial resection of the choledochal cyst ( n = 78) developed associated symptoms, including new cyst, calculus of the bile duct (51/78 [65.4%]), and carcinogenesis (11/78 [14.1%]) in the residual intrapancreatic biliary duct. Post-treatment clinical manifestations were significantly different between patients with partial resection versus whole excision of the choledochal cyst ( P<0.05). Conclusion Surgical re-excision should be considered in patients with a residual intrapancreatic portion of the choledochal cyst due to prior incomplete surgery, regardless of clinical symptoms.

Systematic review, meta-analysis, and a high-volume center experience supporting the new role of mural nodules proposed by the updated 2017 international guidelines on IPMN of the pancreas

BACKGROUND

Mural nodules (MNs) have a predominant role in the 2016 revision of the international guidelines on intraductal papillary mucinous neoplasms (IPMN) of the pancreas. The aim of this study was to evaluate MNs as predictors of invasive cancer (iCa) or high-grade dysplasia (HGD) in IPMNs and to investigate the role of MN size in risk prediction.

METHODS

A PRISMA-compliant systematic review of the literature and meta-analysis on selected studies were conducted. The random effect model was adopted, and the pooled SMD (standardized mean difference) obtained. The surgical series of IPMNs at a single high-volume institution was reviewed.

RESULTS

This review included 70 studies and 2297 resected IPMNs. MNs have a positive predictive value for malignancy of 62.2%. The meta-analysis suggested that MN size has a considerable effect on predicting IPMNs with both iCa or HGD with a mean SMD of 0.79. All studies included in the meta-analysis used contrast-enhanced endosonography (CE-EUS) to assess MNs. Due to the heterogeneity of the proposed thresholds, no reliable MN size cut-off was identified. Of 317 IPMNs resected at our institution, 102 (32.1%) had a preoperative diagnosis of MN. Multivariate analysis showed that MN is the only independent predictor of iCa and HGD for all types of IPMNs.

CONCLUSION

MNs are reliable predictors of iCa and HGD in IPMNs as proposed by the 2016 IAP guidelines. CE-EUS seems to be the best tool for characterizing size and has the best accuracy for predicting malignancy. Further studies should determine potential MN dimensional cut-offs.

Stromal Fibrosis and Expression of Matricellular Proteins Correlate With Histological Grade of Intraductal Papillary Mucinous Neoplasm of the Pancreas

OBJECTIVE

The aim of the study was to clarify the correlation between the microenvironmental factors and histological grade in intraductal papillary mucinous neoplasm (IPMN).

METHODS

We investigated 65 IPMNs resected at Yamagata University Hospital between 2000 and 2011, and all cases were categorized to low-inter (including low- and intermediate-grade dysplasia) and high-inv (including high-grade dysplasia and IPMN with an associated invasive carcinoma) groups. We compared between the 2 groups pathologically with regard to fibrosis and the expression of alpha-smooth muscle actin (α-SMA), periostin, and galectin-1 in the periductal stroma of IPMN.

RESULTS

There were 41 low-inter and 24 high-inv. The subtype was categorized as 22 main duct type (MD-IPMN) and 43 branch duct type (BD-IPMN). The degree of fibrosis and the expression of α-SMA, periostin, and galectin-1 were significantly higher in high-inv than in low-inter within BD-IPMNs. Multivariate logistic regression analysis indicated that high expression of α-SMA (odds ratio, 13.802; 95% confidence interval, 1.108-171.893; P = 0.0414) was a significant independent related factor of high-inv in BD-IPMN.

CONCLUSIONS

Stromal fibrosis and expression of α-SMA, periostin, and galectin-1 are more marked in high-inv than in low-inter within BD-IPMNs, and they could become new markers for determining the indications for surgery in BD-IPMN.