Cystic pancreatic lesions: current evidence for diagnosis and treatment

Pancreatic cystic neoplasms and post-inflammatory cysts: interobserver agreement and diagnostic performance of MRI with MRCP

PURPOSE

We aimed to answer several clinically relevant questions; (1) the interobserver agreement, (2) diagnostic performance of MRI with MRCP for (a) branch duct intraductal papillary mucinous neoplasms (BD-IPMN), mucinous cystic neoplasms (MCN) and serous cystic neoplasms (SCN), (b) distinguishing mucinous (BD-IPMN and MCN) from non-mucinous cysts, and (c) distinguishing three pancreatic cystic neoplasms (PCN) from post-inflammatory cysts (PIC).

METHODS

A retrospective analysis was performed at a tertiary referral center for pancreatic diseases on 71 patients including 44 PCNs and 27 PICs. All PCNs were confirmed by surgical pathology to be 17 BD-IPMNs, 13 MCNs, and 14 SCNs. Main duct and mixed type IPMNs were excluded. Two experienced abdominal radiologists blindly reviewed all the images.

RESULTS

Sensitivity of two radiologists for BD-IPMN, MCN and SCN was 88-94%, 62-69% and 57-64%, specificity of 67-78%, 67-78% and 67-78%, and accuracy of 77-82%, 65-75% and 63-73%, respectively. There was 80% sensitivity, 63-73% specificity, 70-76% accuracy for distinguishing mucinous from non-mucinous neoplasms, and 73-75% sensitivity, 67-78% specificity, 70-76% accuracy for distinguishing all PCNs from PICs. There was moderate-to-substantial interobserver agreement (Cohen's kappa: 0.65).

CONCLUSION

Two experienced abdominal radiologists had moderate-to-high sensitivity, specificity, and accuracy for BD-IPMN, MCN, and SCN. The interobserver agreement was moderate-to-substantial. MRI with MRCP can help workup of incidental pancreatic cysts by distinguishing PCNs from PICs, and premalignant mucinous neoplasms from cysts with no malignant potential.

Clinicoradiological features of resected serous cystic neoplasms according to morphological subtype and preoperative tentative diagnosis: can radiological characteristics distinguish serous cystic neoplasms from other lesions?

Purpose

Serous cystic neoplasm (SCN) of the pancreas is considered benign in most cases. However, some SCN patients undergo surgical resection because lesions could not be differentiated preoperatively. This study evaluated causes of resection for SCN, investigated clinical and radiological features of surgically resected SCNs, and compared characteristics of SCNs diagnosed accurately and those misdiagnosed.

Methods

One hundred patients, who underwent surgery for pancreatic cystic tumors with pathological confirmation of SCN between 2000 and 2014 were retrospectively analyzed.

Results

The mean patient age was 52.9 years, 67 (67%) were female, and most lesions (72%) were located in the pancreatic body or tail. Fifty-one (51%) pathologically confirmed SCNs were preoperatively diagnosed as non-SCNs. Patients underwent surgery due to uncertain diagnosis (58%) or symptomatology (18%). According to radiological examination, most lesions were macrocystic (85%), exhibited septation (58%), or were enhancing lesions (48%). Compared with preoperatively diagnosed non-SCNs, accurately diagnosed SCNs exhibited septation (75.5% vs. 41.2%, P = 0.001) and central scar (36.7% vs. 11.8%, P = 0.003) more frequently in radiological examinations. In terms of macrocystic tumors (n = 85), most parameters did not differentiate preoperative diagnoses, although lesions accurately diagnosed as SCN exhibited septation more frequently than those preoperatively misdiagnosed as mucinous cystic neoplasm or intraductal papillary mucinous neoplasm (70.7% vs. 38.9% vs. 33.3%, respectively, P = 0.009).

Conclusion

It is difficult to accurately distinguish macrocystic SCNs from other cystic tumors using conventional radiological methods. For more accurate diagnosis, new biomarkers and/or other diagnostic modalities are needed and warrant further investigation.

Cystic neoplasms of the pancreas; findings on magnetic resonance imaging with pathological, surgical, and clinical correlation

Pancreatic cysts are increasingly being identified by cross-sectional imaging studies. Pancreatic cystic lesions comprise a spectrum of underlying pathologies ranging from benign and pre-malignant lesions to frank malignancies. Magnetic resonance imaging with cholangiopancreatography is a non-invasive imaging modality used for the characterization of cystic pancreatic lesions. This article will review the most common pancreatic cystic neoplasms and the utility of MR imaging in the characterization of these cysts.

Diagnostic utility of clinical and biochemical parameters in pancreatic head malignancy patients with normal carbohydrate antigen 19-9 levels

BACKGROUND

Carbohydrate antigen (CA)19-9 that is the most widely used biomarker for pancreatic cancer has certain limitations in diagnosis, which results in a tough job to distinguish pancreatic cancer from benign tumors with normal CA19-9. The aim of this study was to investigate the diagnostic utility of clinical parameters and serum markers in patients with pancreatic head masses but without elevated CA19-9.

METHODS

Retrospectively, 106 (69 malignant, 37 benign) of 487 patients admitted for pancreatic head masses were enrolled with CA19-9 level of <37u/ml. Clinical parameters and serum biomarkers were assessed. Among the patients with pancreatic head mass, male individuals (p=0.025) and elder individuals (p<0.001) were more likely to have cancer; and cancer patients were more likely to present with abdominal-pain (p=0.023), weight-loss (p=0.013) and jaundice (p<0.001). Serum bilirubin levels among malignancies, including total bilirubin (p<0.001), direct bilirubin (p<0.001) and indirect bilirubin (p<0.001), were considerably higher than those of benign ones. Logistic regression further concluded that age-distribution, abdominal-pain and direct-bilirubin were three independent factors correlating with final diagnosis. However, CEA (p=0.156) was not sufficient enough to exclude pancreatic cancer.

CONCLUSIONS

In patients with pancreatic head masses and CA19-9 of <37u/ml, age-distribution, abdominal-pain and direct bilirubin might be helpful in differential diagnosis. CEA was insufficient for exclusion of malignancy.

The incidental cystic pancreas mass: a practical approach

Technical advances in cross-sectional imaging have led to the discovery of incidental cystic pancreatic lesions in the oncology and non-oncology population that in the past remained undetected. These lesions have created a diagnostic and management dilemma for both clinicians and radiologists: should these lesions be ignored, watched, aspirated, or removed? In this review, recommendations concerning the assessment of the more common pancreatic cystic incidental lesions are presented.

[Intraductal papillary mucinous neoplasia: which findings support observation?]

On abdominal CT scans asymptomatic cystic lesions of the pancreas are accidentally detected in 1-2% of patients. Congenital cysts and pancreatic pseudocysts account for two thirds of these lesions. Pancreatic pseudocysts are a frequent complication of acute and chronic pancreatitis. Among resected cystic neoplasms serous cystic adenoma accounts for 30%, mucinous cystic neoplasms for 45% and intraductal papillary mucinous neoplasms for 25%. The diagnosis of a cystic pancreatic lesion is usually made by diagnostic imaging. Symptomatic lesions require definitive therapeutic treatment after appropriate diagnostic work-up. In the diagnosis of asymptomatic cystic lesions several factors are important, among them whether the cyst is connected to the pancreatic duct (as in IPMN and pseudocysts), the size of lesion (for treatment indications) and whether nodules form in the wall of the cyst (a sign of potential malignancy). EUS-guided fine needle aspiration of the cyst fluid adds to the discrimination between benign, premalignant and malignant cystic lesions. Measuring lipase activity, CEA, viscosity and mucin as well as cytology can help in differentiating cystic lesions. An algorithm is discussed for the differential diagnosis and for selection of the appropriate treatment for pancreatic cystic lesions, most of which never require surgery.

Comparison of surgical and endoscopic sample collection for pancreatic cyst fluid biomarker identification

Significant efforts are underway to develop new biomarkers from pancreatic cyst fluid. Previous research has made use of cyst fluid collected from surgically removed cysts, but the clinical implementation of biomarkers would use cyst fluid collected by endoscopic ultrasound-guided, fine-needle aspiration (EUS-FNA). The purpose of this study was to investigate the clinical applicability of cyst fluid research obtained using surgical specimens. Matched pairs of operating-room collected (OR) and EUS-FNA samples from 12 patients were evaluated for the levels of three previously described biomarkers, CA 19-9, CEA, and glycan levels detected by wheat germ agglutinin on MUC5AC (MUC5AC-WGA). CA 19-9 and MUC5AC-WGA correlated well between the sample types, although CEA was more variable between the sample types for certain patients. The variability was not due to the time delay between EUS-FNA and OR collection or differences in total protein concentrations but may be caused by contamination of the cyst fluid with blood proteins. The classification of each patient based on thresholds for each marker was perfectly consistent between sample types for CA 19-9 and MUC5AC-WGA and mostly consistent for CEA. Therefore, results obtained using OR-collected pancreatic cyst fluid samples should reliably transfer to the clinical setting using EUS-FNA samples.