Pancreatic cysts: What imaging characteristics are associated with development of pancreatic ductal adenocarcinoma?

An Exosomal miRNA Biomarker for the Detection of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a difficult tumor to diagnose and treat. To date, PDAC lacks routine screening with no markers available for early detection. Exosomes are 40-150 nm-sized extracellular vesicles that contain DNA, RNA, and proteins. These exosomes are released by all cell types into circulation and thus can be harvested from patient body fluids, thereby facilitating a non-invasive method for PDAC detection. A bioinformatics analysis was conducted utilizing publicly available miRNA pancreatic cancer expression and genome databases. Through this analysis, we identified 18 miRNA with strong potential for PDAC detection. From this analysis, 10 (MIR31, MIR93, MIR133A1, MIR210, MIR330, MIR339, MIR425, MIR429, MIR1208, and MIR3620) were chosen due to high copy number variation as well as their potential to differentiate patients with chronic pancreatitis, neoplasms, and PDAC. These 10 were examined for their mature miRNA expression patterns, giving rise to 18 mature miRs for further analysis. Exosomal RNA from cell culture media was analyzed via RTqPCR and seven mature miRs exhibited statistical significance (miR-31-5p, miR-31-3p, miR-210-3p, miR-339-5p, miR-425-5p, miR-425-3p, and miR-429). These identified biomarkers can potentially be used for early detection of PDAC.

Non-branched microcysts of the pancreas on MR imaging of patients with pancreatic tumors who had pancreatectomy may predict the presence of pancreatic intraepithelial neoplasia (PanIN): a preliminary study

PURPOSE

To evaluate whether pancreatic parenchymal abnormalities on magnetic resonance imaging (MRI) are associated with pancreatic intraepithelial neoplasia (PanIN) on histology.

MATERIALS AND METHODS

Retrospective study approved by institutional review board. One hundred patients (48 men, 52 women; mean age, 53.2 ± 16.29 [SD]) underwent MRI before pancreatectomy for pancreatic tumors analyzed by two independent observers blinded to histopathological results for the presence of non-communicating microcysts and pancreatic atrophy (global or focal) beside tumors. MRI findings were compared to histopathological findings of resected specimens. Interobserver agreement was calculated. The association between parenchymal abnormalities and presence of PanIN was assessed by uni- and multivariate analyses.

RESULTS

PanIN was present in 65/100 patients (65%). The presence of microcysts on MRI had a sensitivity of 52.3% (34/65 [95%CI, 51.92-52.70%]), a specificity of 77.1% (27/35 [95%CI, 76.70-77.59]), and accuracy of 61% (61/100 95%CI [50.7-70.6]) for the diagnosis of PanIN while global atrophy had a sensitivity of 24.6% (16/6 [95%CI, 24.28-24.95]) and a specificity of 97.1% (34/35 [95%CI, 96.97-97.32%]). In multivariate analysis, the presence of microcysts (OR, 3.37 [95%CI, 1.3-8.76]) (p = 0.0127) and global atrophy (OR, 9.79 [95%CI, 1.21-79.129]) (p = 0.0324) were identified as independent predictors of the presence of PanIN. The combination of these two findings was observed in 10/65 PanIN patients and not in patients without PanIN (p = 0.013 with an OR of infinity [95%CI, 1.3-infinity]) and was not discriminant for PanIN-3 and lower grade (p = 0.22). Interobserver agreement for the presence of microcysts was excellent (kappa = 0.92), and for the presence of global atrophy, it was good (kappa = 0.73).

CONCLUSION

The presence of non-communicating microcysts on pre-operative MRI can be a significant predictor of PanIN in patients with pancreatic tumors.

KEY POINTS

• In patients with pancreatic tumors who had partial pancreatectomy, MR non-communicating pancreatic microcysts have a 52.3% sensitivity, a 77.1% specificity, and a 61% accuracy for the presence of PanIN with univariate and with an odds ratio of 3.37 with multivariate analyses. • The association of global atrophy and non-communicating microcysts increases the predictive risk of PanIN.

Risk of pancreatitis after pancreatic duct guidewire placement during endoscopic retrograde cholangiopancreatography

BACKGROUND & AIMS

Advanced techniques have been developed to overcome difficult cannulation cases in endoscopic retrograde cholangiopancreatography (ERCP). Pancreatic duct guidewire placement method (PGW) is performed in difficult cannulation cases; it is possible that it places patients at risk of post-ERCP pancreatitis (PEP). The mechanism of PEP is still unclear, but pancreatic duct pressure and injury of pancreatic duct are known causes of PEP. Therefore, we hypothesized a relationship between pancreatic duct diameter and PEP and predicted that PGW would increase the risk of PEP in patients with non-dilated pancreatic ducts. This study aimed to investigate whether PGW increased the risk of PEP in patients with pancreatic duct diameter ≤ 3 mm.

METHODS

We analyzed 332 patients with pancreatic duct ≤ 3 mm who performed first time ERCP session. The primary endpoint was the rate of adverse event of PEP. We evaluated the risk of PEP in patients who had undergone PGW compared to those who had not, using the inverse probability of treatment weighting (IPTW) analysis.

RESULTS

PGW was found to be an independent risk factor for PEP by univariate analysis (odds ratio [OR], 2.45; 95% confidence interval [CI], 1.12-5.38; p = 0.03) after IPTW in patients with pancreatic duct diameter ≤ 3 mm. Adjusted for all covariates, PGW remained an independent risk factor for PEP (OR, 3.12; 95% CI, 1.33-7.33; p = 0.01).

CONCLUSION

Our results indicate that PGW in patients with pancreatic duct diameter ≤ 3 mm increases the risk of PEP.

Imaging Pancreatic Cysts with CT and MRI

CT and MRI are the imaging modalities of choice to guide the clinical management of incidentally discovered pancreatic cysts. Most of these lesions are mucinous cysts with varying degrees of malignant potential. This article reviews the CT and MRI findings that help differentiate a potentially aggressive lesion that requires EUS or surgery from a lesion of low malignant potential that is appropriate for imaging surveillance. The imaging-based societal guidelines for these cysts are reviewed.