Radiomics advances in the evaluation of pancreatic cystic neoplasms

With the development of medical imaging, the detection rate of pancreatic cystic neoplasms (PCNs) has increased greatly. Serous cystic neoplasm, solid pseudopapillary neoplasm, intraductal papillary mucinous neoplasm and mucinous cystic neoplasm are the main subtypes of PCN, and their treatment options vary greatly due to the different biological behaviours of the tumours. Different from conventional qualitative imaging evaluation, radiomics is a promising noninvasive approach for the diagnosis, classification, and risk stratification of diseases involving high-throughput extraction of medical image features. We present a review of radiomics in the diagnosis of serous cystic neoplasm and mucinous cystic neoplasm, risk classification of intraductal papillary mucinous neoplasm and prediction of solid pseudopapillary neoplasm invasiveness compared to conventional imaging diagnosis. Radiomics is a promising tool in the field of medical imaging, providing a noninvasive, high-performance model for preoperative diagnosis and risk stratification of PCNs and improving prospects regarding management of these diseases. Further studies are warranted to investigate MRI image radiomics in connection with PCNs to improve the diagnosis and treatment strategies in the management of PCN patients.

Endoscopic ultrasound-guided fine-needle aspiration for pancreatic cystic lesions: a comprehensive review

Advancements in diagnostic radiology have amplified the incorporation of these techniques into routine clinical practice. Concurrently, the frequency of incidentally identifying pancreatic cystic lesions (PCLs) has surged. PCLs encompass diverse categories contingent upon their origin. Among them, branch duct-intraductal papillary mucinous neoplasms (BD-IPMN) and mucinous cystic neoplasms (MCN) are categorized as mucinous cystic lesions that have malignant potential. Even solid neoplasms occasionally show cystic degeneration. Therefore, precise differential PCL diagnosis is crucial to optimize clinical management strategies and detect malignant transformations. Endoscopic ultrasound (EUS) affords comprehensive visualization of the pancreas with high-resolution ultrasound, complemented by fine-needle aspiration (FNA) under real-time EUS guidance, which is a minimally invasive procedure for obtaining pathological samples. This synergy has established EUS and EUS-FNA as vital procedures in the management of PCLs, enabling differentiation of PCLs. Cyst fluid analysis has played a pivotal role in deciding the optimal management strategy. The efficacy of cytological analysis is limited by scant cytologic material. The "string sign" test evaluates fluid viscosity, and its simplicity warrants initial consideration. Amylase and tumor markers, such as CEA, have been studied, but they yield varied sensitivity and specificity. Glucose and genetic mutations (KRAS, GNAS) exhibit promise, while comprehensive genomic profiling underscores genetic insights. Through-the-needle biopsy and needle-based confocal laser endomicroscopy also show high diagnostic yield. EUS-FNA, however, entails risks like infection and needle tract seeding, emphasizing the need for proper utilization. Pancreatic cyst fluid analysis augments diagnostic accuracy and informs clinical decisions, making it a valuable adjunct to imaging.

A Case of Multicystic Biliary Hamartoma with a Marked Peribiliary Gland Component Successfully Treated by Purely Laparoscopic Anatomical Liver Resection

BACKGROUND

Multicystic biliary hamartoma (MCBH) is an extremely rare benign liver lesion characterized by a gross well-circumscribed multicystic honeycomb appearance. This report presents a MCBH case with a marked peribiliary gland component which showed unusual histology.

CASE PRESENTATION

A 63-year-old Japanese male was admitted to our hospital for a detailed examination of a hepatic cystic lesion, which was originally detected 14 years ago and had slowly enlarged. A preoperative imaging study revealed a well-demarcated multicystic lesion without communication to the biliary tracts. The possible clinical diagnoses were mucinous cystic neoplasm (MCN) or MCBH. The lesion was successfully resected by purely laparoscopic right anterior sectionectomy. The cut surfaces of resected specimens grossly exhibited a well-circumscribed multicystic lesion with a thick septum. Histologically, the cyst wall was covered by cuboidal epithelial cells resembling epithelium of the bile duct while abundant small ducts, which morphologically resembled peribiliary glands, were observed among the fibrous stroma of the thick septum. Although possible pathological diagnosis varied, including intrahepatic cholangiocarcinoma, intraductal papillary neoplasm of the bile duct, biliary adenofibroma, MCN and MCBH, the lesion was finally diagnosed as MCBH with a marked peribiliary gland component.

CONCLUSIONS

MCBH can contain abundant peribiliary glands in the fibrous stroma. A pathologist should be careful not to diagnose such peribiliary glands in MCBH as neoplastic glands.

Clinical and Molecular Attributes and Evaluation of Pancreatic Cystic Neoplasm

Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are all considered "Pancreatic cystic neoplasms (PCNs)" and show a varying risk of developing into pancreatic ductal adenocarcinoma (PDAC). These lesions display different molecular characteristics, mutations, and clinical manifestations. A lack of detailed understanding of PCN subtype characteristics and their molecular mechanisms limits the development of efficient diagnostic tools and therapeutic strategies for these lesions. Proper in vivo mouse models that mimic human PCNs are also needed to study the molecular mechanisms and for therapeutic testing. A comprehensive understanding of the current status of PCN biology, mechanisms, current diagnostic methods, and therapies will help in the early detection and proper management of patients with these lesions and PDAC. This review aims to describe all these aspects of PCNs, specifically IPMNs, by describing the future perspectives.

Integrating Molecular Analysis into the Pathologic Evaluation of Pancreatic Cysts

The development of cross-sectional imaging techniques has enhanced the detection of pancreatic cystic lesions (PCLs). PCLs are found in approximately 2% of the general population, often as incidentally detected lesions on computed tomography or MRI during the evaluation of other medical conditions. Broadly, PCLs are classified as mucinous or nonmucinous. Mucinous PCLs include mucinous cystic neoplasms and intraductal papillary mucinous neoplasms. Nonmucinous PCLs include pseudocysts, serous cystadenomas, solid pseudopapillary neoplasms, and cystic pancreatic neuroendocrine tumors, as well as cystic acinar cell carcinoma, cystic degeneration of pancreatic ductal adenocarcinoma, lymphoepithelial cyst, and others.

A case of pancreatic mucinous cystadenocarcinoma with malignant ascites without recurrence for more than 8 years after surgery

Mucinous cystadenocarcinoma (MCAC) with malignant ascites is rare. We report a case of a 28-year-old woman who presented with epigastric pain. The ascites in the Douglas fossa was identified at a nearby gynecology clinic. Computed tomography showed a multiloculated cystic lesion (9.5 × 6.4 cm) in the tail of the pancreas, which was diagnosed as mucinous cystic neoplasm on imaging. Staging laparoscopy was performed, and rapid cytology of ascites revealed adenocarcinoma, leading to a diagnosis of unresectable MCAC. Subsequently, combination chemotherapy with gemcitabine plus S-1 was initiated. Although there were no remarkable changes in the imaging findings, the peritoneal dissemination node was not consistently recognized in any of the imaging findings, and distal pancreatectomy was performed. A peritoneal dissemination node was not observed in the laparotomy findings, but the peritoneal lavage cytology was positive. The postoperative pathological result was non-invasive MCAC, and the ascites was suspected to be caused by cyst rupture. The patient has been recurrence-free, including the reappearance of ascites, for > 8 years after adjuvant therapy with S-1. Although careful follow-up will be required in the future, the very good prognosis in this case suggests that MCAC with malignant ascites without obvious peritoneal dissemination should be considered for surgical resection.

Role of endoscopic ultrasound and cyst fluid tumor markers in diagnosis of pancreatic cystic lesions

BACKGROUND

Pancreatic cystic lesions (PCLs) are common in clinical practice. The accurate classification and diagnosis of these lesions are crucial to avoid unnecessary treatment of benign lesions and missed opportunities for early treatment of potentially malignant lesions.

AIM

To evaluate the role of cyst fluid analysis of different tumor markers such as cancer antigens [e.g., cancer antigen (CA)19-9, CA72-4], carcinoembryonic antigen (CEA), serine protease inhibitor Kazal-type 1 (SPINK1), interleukin 1 beta (IL1-β), vascular endothelial growth factor A (VEGF-A), and prostaglandin E2 (PGE2)], amylase, and mucin stain in diagnosing pancreatic cysts and differentiating malignant from benign lesions.

METHODS

This study included 76 patients diagnosed with PCLs using different imaging modalities. All patients underwent endoscopic ultrasound (EUS) and EUS-fine needle aspiration (EUS-FNA) for characterization and sampling of different PCLs.

RESULTS

The mean age of studied patients was 47.4 ± 11.4 years, with a slight female predominance (59.2%). Mucin stain showed high statistical significance in predicting malignancy with a sensitivity of 87.1% and specificity of 95.56%. It also showed a positive predictive value and negative predictive value of 93.1% and 91.49%, respectively (P < 0.001). We found that positive mucin stain, cyst fluid glucose, SPINK1, amylase, and CEA levels had high statistical significance (P < 0.0001). In contrast, IL-1β, CA 72-4, VEGF-A, VEGFR2, and PGE2 did not show any statistical significance. Univariate regression analysis for prediction of malignancy in PCLs showed a statistically significant positive correlation with mural nodules, lymph nodes, cyst diameter, mucin stain, and cyst fluid CEA. Meanwhile, logistic multivariable regression analysis proved that mural nodules, mucin stain, and SPINK1 were independent predictors of malignancy in cystic pancreatic lesions.

CONCLUSION

EUS examination of cyst morphology with cytopathological analysis and cyst fluid analysis could improve the differentiation between malignant and benign pancreatic cysts. Also, CEA, glucose, and SPINK1 could be used as promising markers to predict malignant pancreatic cysts.

State-of-the-Art Update of Pancreatic Cysts

Andrew Canakis.

Differentiation of mucinous cysts and simple cysts of the liver using preoperative imaging

PURPOSE

Preoperative radiographic differentiation of mucinous cystic neoplasms (MCN) and simple cysts (SLC) of the liver is challenging. Previous data have demonstrated that the finding of septations arising from the cyst wall without indentation on cross-sectional imaging is associated with MCN. We aim to assess whether this radiographic feature is diagnostic of MCN.

METHODS

A prospectively maintained database was queried for patients with a preoperative diagnosis of a cystic liver lesion who subsequently underwent operative intervention. The feature of septations without indentation of the cyst wall was evaluated on cross-sectional imaging obtained within 3 months of operation. Imaging was independently evaluated by three radiologists blinded to pathology and interobserver agreement was compared to assess the diagnostic accuracy of this feature as well as the overall likelihood of the lesion representing a MCN.

RESULTS

There were 95 patients who met inclusion criteria; 80 (84%) had SLC on pathology, while 15 (16%) had MCN. Presence of septa without indentation of cyst wall had high sensitivity (range 80-87%), but low specificity (range 48-66%). Interobserver percent agreement (PA) was 51% [κ = 0.35 (95% CI 0.22-0.47)]. Sensitivity among the three radiologists ranged between 20 and 80% and specificity between 71 and 91% for the likelihood of the lesion representing MCN versus SLC, with an area under the curve (AUC) of 0.67-0.79; however, interobserver agreement was fair [κ = 0.40 (95% CI 0.25-0.55), PA = 67%].

CONCLUSION

The presence of septations without indentation of cyst wall demonstrates adequate sensitivity to differentiate MCN and SLC. However, there is variability for detection of this feature and therefore, it alone is of limited clinical value.

Recent advances in the diagnostic evaluation of pancreatic cystic lesions

Pancreatic cystic lesions (PCLs) are becoming more prevalent due to more frequent abdominal imaging and the increasing age of the general population. It has become crucial to identify these PCLs and subsequently risk stratify them to guide management. Given the high morbidity associated with pancreatic surgery, only those PCLs at high risk for malignancy should undergo such treatment. However, current diagnostic testing is suboptimal at accurately diagnosing and risk stratifying PCLs. Therefore, research has focused on developing new techniques for differentiating mucinous from non-mucinous PCLs and identifying high risk lesions for malignancy. Cross sectional imaging radiomics can potentially improve the predictive accuracy of primary risk stratification of PCLs at the time of detection to guide invasive testing. While cyst fluid glucose has reemerged as a potential biomarker, cyst fluid molecular markers have improved accuracy for identifying specific types of PCLs. Endoscopic ultrasound guided approaches such as confocal laser endomicroscopy and through the needle microforceps biopsy have shown a good correlation with histopathological findings and are evolving techniques for identifying and risk stratifying PCLs. While most of these recent diagnostics are only practiced at selective tertiary care centers, they hold a promise that management of PCLs will only get better in the future.

RNF43 as a predictor of malignant transformation of pancreatic mucinous cystic neoplasm

Mucinous cystic neoplasm (MCN) of the pancreas rarely progresses to invasive carcinoma, but few studies have analyzed genomic alterations involved in its malignant transformation. The relationships of ring finger protein 43 (RNF43) mutations with cytological atypia, RNF43 protein expression, and Wnt signaling proteins in MCN remain unclear. This study included 106 MCN cases, classified into 89 low-grade dysplasia (LG), 9 high-grade dysplasia (HG), and 8 invasive carcinoma (INV). We analyzed HG/INV and LG lesions of 9 HG/INV cases and LG lesions of 9 LG cases using targeted sequencing and confirmed the protein expression of RNF43 and β-catenin. The frequency of RNF43 mutations was significantly higher in HG/INV cases than in LG cases. Furthermore, HG/INV lesions (56%) and LG lesions (33%) of HG/INV cases possessed RNF43 mutation, whereas no such mutation was detected in any LG cases. The expression of RNF43 was reduced in 71% of HG/INV cases and significantly correlated with histological grade and aberrant expression of β-catenin. In 3 of 5 RNF43-mutated cases, the expression of RNF43 was reduced, but there was no significant correlation between RNF43 mutation and protein expression. MCNs frequently harbored KRAS mutations, at rates of 100% in HG/INV lesions and 50% in LG lesions of HG/INV and LG cases. There was no significant difference in mutation frequency in LG lesions between HG/INV and LG cases. These results suggest that RNF43 mutations may be involved in and predictive of malignant transformation from an early stage of MCN.

Pancreatic Cysts after Endoscopic Ultrasonography-Guided Ethanol and/or Paclitaxel Ablation Therapy: Another Mimic of Pancreatic Pseudocysts

BACKGROUND

Endoscopic ultrasound-guided ablation (EUS-A) therapy is a minimally invasive procedure for pancreatic-cystic tumors in patients with preoperative comorbidities or in patients who are not indicated for surgical resection. However, histopathologic characteristics of pancreatic cysts after ablation have not been well-elucidated.

METHODS

Here, we analyzed pathological findings of 12 surgically resected pancreatic cysts after EUS-A with ethanol and/or paclitaxel injection.

RESULTS

Mean patient age was 49.8 ± 13.6 years with a 0.3 male/female ratio. Clinical impression before EUS-A was predominantly mucinous cystic neoplasms. Mean cyst size before and after ablation therapy was similar (3.7 ± 1.0 cm vs. 3.4 ± 1.6 cm; p = 0.139). Median duration from EUS-A to surgical resection was 18 (range, 1-59) months. Mean percentage of the residual neoplastic lining epithelial cells were 23.1 ± 37.0%. Of the resected cysts, 8 cases (67%) showed no/minimal (<5%) residual lining epithelia, while the remaining 4 cases (33%) showed a wide range of residual mucinous epithelia (20-90%). Ovarian-type stroma was noted in 5 cases (42%). Other histologic features included histiocytic aggregation (67%), stromal hyalinization (67%), diffuse egg shell-like calcification along the cystic wall (58%), and fat necrosis (8%).

CONCLUSION

Above all, diffuse egg shell-like calcification along the pancreatic cystic walls with residual lining epithelia and/or ovarian-type stroma were characteristics of pancreatic cysts after EUS-A. Therefore, understanding these histologic features will be helpful for precise pathological diagnosis of pancreatic cystic tumor after EUS-A, even without knowing the patient's history of EUS-A.

Pancreatic cystic neoplasms: a review of current recommendations for surveillance and management

Pancreatic cystic neoplasms (PCN) comprise of a diverse array of pancreatic cysts, including intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), serous cystic neoplasms (SCN), cystic neuroendocrine tumors (cNET), and many others. Increasing use of cross-sectional imaging has resulted in greater numbers of PCNs discovered incidentally. The overall risk of malignancy is low, but can vary considerably between different classes of PCNs. Furthermore, many pancreatic cysts are indeterminate on imaging, and the inability to reliably predict the course of disease remains a challenge for radiologists. Due to the variability in disease course and a lack of high-quality studies on PCNs, there is no universal consensus when it comes to balancing optimal surveillance while avoiding the risk for overtreatment. Currently, there are three widely accepted international guidelines outlining guidelines for surveillance and management of PCNs: the American Gastroenterological Association (AGA) in 2015, the International Association of Pancreatology (IAP) last revised in 2017, and the European Study Group on Cystic Tumours of the Pancreas (European) last revised in 2018. In 2017, the American College of Radiology released its own comprehensive set of recommendations for managing indeterminate pancreatic cysts that are detected incidentally on CT or MRI. The purpose of this paper is to describe the key differences between the ACR recommendations and the aforementioned three sets of guidelines regarding cyst management, imaging surveillance, performance, and cost-effectiveness.

A mucinous cystic neoplasm of the pancreas containing an undifferentiated carcinoma component and harboring the NRAS driver mutation

A woman in her 20s visited our hospital with a chief complaint of abdominal distension and back pain. She was diagnosed with a cystic tumor (diameter 16 cm) in the tail of the pancreas and underwent a combined distal pancreatectomy, splenectomy, and left adrenalectomy. Histopathologically, the tumor presented as a mucinous cystic neoplasm with an undifferentiated carcinoma component of the pancreas. In addition, the cells demonstrated a partial rhabdoid-like morphology. These findings were considered relatively typical for a mucinous cystic neoplasm in the tail of the pancreas in a young woman. However, NRAS mutation, which is rare in pancreatic tumors, was detected.

CT and MRI features differentiating mucinous cystic neoplasms of the liver from pathologically simple cysts

PURPOSE

The purpose of this study was to determine if CT and MRI features can accurately differentiate mucinous cystic neoplasms (MCNs) from simple liver cysts and to compare accuracy of CT and MRI in detecting these features.

METHODS

Eighty-four surgically treated lesions with pre-operative CT or MRI were evaluated by two abdominal radiologists for upstream biliary dilatation, perfusional change, internal hemorrhage, thin septations, thick septations/nodularity, lobar location, and number of coexistent liver cysts. Odds ratios, sensitivities, specificities, and positive and negative predictive values were calculated for association of each feature with MCNs.

RESULTS

Of 84 liver lesions, 13 (15%) were MCNs, all in women, and 71 (85%) were simple cysts, in 59 women and 12 men. Thick septations/nodularity, upstream biliary dilation, thin septations, internal hemorrhage, perfusional change, and fewer than 3 coexistent liver cysts were more frequent in MCNs than in simple cysts. The combination of thick septations/nodularity and at least one additional associated feature showed high specificity for MCNs (94-98%). MRI detected significant associations of biliary dilation, thin septations, and hemorrhage/debris with MCNs which CT did not.

CONCLUSION

Surgically treated MCNs of the liver with preoperative imaging occurred at our institution only in women. Thick septations or nodularity, biliary dilation, thin septations, internal hemorrhage or debris, perfusional change, and fewer than 3 coexistent liver cysts are features that help differentiate MCNs from simple cysts. MRI has advantages over CT in detecting these features.

Molecular and Immunohistochemical Analysis of Mucinous Cystic Neoplasm of the Liver

OBJECTIVES

Mucinous cystic neoplasm of the liver is characterized by neoplastic mucinous and/or biliary epithelium surrounded by ovarian-type stroma. Immunohistochemical studies have shown that the ovarian-type stroma expresses estrogen receptor, suggesting potential hormonal responsiveness. The molecular biology of mucinous cystic neoplasm of the liver remains poorly studied.

METHODS

Transcriptome sequencing and immunohistochemistry were performed on a series of mucinous cystic neoplasms.

RESULTS

Mucinous cystic neoplasm of the liver exhibited significantly increased RNA expression of ovarian stromal markers WT1, PR, and ER2 and sex cord stromal markers SF-1, inhibin-α, and calretinin compared with nonneoplastic liver. Immunohistochemistry confirmed the RNA-level data. Evidence for sex hormone biosynthesis was identified by significant overexpression of multiple estrogen biosynthetic enzymes. Expression of 17β-hydroxysteroid dehydrogenase 1 was confirmed immunohistochemically. Pathway analysis also identified significant upregulation of the hedgehog and Wnt pathways and significant downregulation of T-helper 1 and T-helper 2 pathways.

CONCLUSIONS

Mucinous cystic neoplasm of the liver recapitulates ovarian stroma at the morphologic, DNA, RNA, and protein levels. These data support the concept that this tumor likely arises from ectopic primitive gonadal tissue and/or stromal cells with capacity to transdifferentiate to ovarian cortical cells.

Mucinous cystic adenoma with inflammatory cell infiltration around the splenic artery mimicking pancreatic cancer: a case report

A 45-year-old woman presented with upper abdominal and back pain. A cystic lesion in the pancreas and inflammation around the splenic artery were detected by computed tomography. Although imaging studies were difficult to exclude malignancy, pathological and cytological findings of a fine-needle aspiration showed no signs of malignancy. The patient was, therefore, followed-up for 3 months, during which time the cyst increased in size and developed a cyst-in-cyst structure. She was diagnosed with mucinous cyst neoplasm and underwent distal pancreatectomy. Histologically, the patient was diagnosed as low-grade mucinous cystic adenoma. Soft tissue shadows around the splenic artery were considered to indicate fibrosis and infiltration of inflammatory cells. After distal pancreatectomy, the patient has been uneventful with symptom resolution. This case highlights the potentially atypical presentation of mucinous cystic neoplasms with inflammatory cell infiltration around the splenic artery.

Endoscopic Ultrasound-Guided Fine Needle Aspiration Cytologic Evaluation of Intraductal Papillary Mucinous Neoplasm and Mucinous Cystic Neoplasms of Pancreas

OBJECTIVES

To evaluate the role of endoscopic ultrasound-guided fine needle aspiration cytology in identifying mucinous cystic lesions (MCLs) in histologically proven cases of intraductal papillary mucinous neoplasm (IPMN) or mucinous cystic neoplasm (MCN) and risk of malignancy associated with each cytologic category based on the Papanicolaou Society of Cytopathology (PSC) guidelines.

METHODS

All resected cases with histologic diagnosis of IPMN or MCN at our institution from January 1, 2004, to August 31, 2019, with associated cytology were included. Available cytology slides of nondiagnostic (ND), negative/benign (BN), and atypical cytology (AC) cases were reviewed and reclassified based on the PSC guidelines.

RESULTS

A total of 120 cases were identified, including 57 IPMNs with low-grade or moderate dysplasia (LGD/MD) and high-grade dysplasia (HGD), 34 MCNs with LGD/MD or HGD, and 29 IPMNs with invasive malignancy. After cytology slide review and reclassification, we observed that ND and BN cases were paucicellular and lacked ancillary testing (carcinoembryonic antigen levels or KRAS mutation analysis). The risk-of-malignancy rates were 33% for ND, 11% for BN, 28.5% for AC, 17% for MCL, and 100% for suspicious/positive cytologic diagnosis.

CONCLUSIONS

A multidisciplinary approach including combined use of cytology and ancillary testing is helpful in establishing a diagnosis of MCL and identifying associated malignancy.

Discrimination of serous cystadenoma from mucinous cystic neoplasm and branch duct intraductal papillary mucinous neoplasm in the pancreas with CT

PURPOSE

The imaging features of serous cystadenomas (SCAs) overlap with those of mucinous cystic neoplasms (MCNs) and branch duct intraductal papillary mucinous neoplasms (BD-IPMNs), and an accurate preoperative diagnosis is important for clinical treatment due to their different biological behaviors. The aim of this study was to provide a computed tomographic (CT) feature for the diagnosis of SCAs and estimate whether the "circumvascular sign" can contribute to the discrimination of SCAs from MCNs and BD-IPMNs.

METHODS

From August 2011 through December 2019, a total of 71 patients (30 patients with 30 SCAs, 21 patients with 21 MCNs and 20 patients with 22 BP-IPMNs) were enrolled in this study. All patients underwent CT examination and were confirmed by surgical pathology. In addition to patient clinical information, CT features (e.g., location, shape) were evaluated via CT.

RESULTS

Central scarring, central calcification and the circumvascular sign were found to be specific CT features for the diagnosis of SCAs and their differential diagnosis from MCNs and BD-IPMNs. All three CT features had high specificity, and both central scarring and central calcification had low sensitivity. When any one of these two features was combined with the circumvascular sign, the sensitivity increased to 83.3%.

CONCLUSION

Pancreatic cystic neoplasms that show central scarring, central calcification or the circumvascular sign on CT could be diagnosed as SCAs. When either of the first two features is combined with the circumvascular sign, the diagnostic sensitivity could be increased.

Pearls and pitfalls of imaging features of pancreatic cystic lesions: a case-based approach with imaging-pathologic correlation

A variety of neoplastic and non-neoplastic lesions of the pancreas can present with a predominantly cystic architecture. These lesions are increasingly being detected as incidental findings on routine cross-sectional imaging following technological advances in these techniques and their widespread use. The different histopathological behaviors show various common and uncommon imaging findings, and some cases show similar appearance in spite of different histopathology. Each lesion requires specific management because of the differing risk of progression to malignancy, and an accurate imaging diagnosis is crucial. The typical imaging characteristics that differentiate pancreatic cystic lesions have been well described and fully summarized. However, in addition to a small percentage of cases that shows uncommon imaging findings, a substantial percentage of cystic lesions shows overlapping imaging findings that can lead to radiological misdiagnosis. For appropriate diagnosis and optimal treatment strategy, it is important to know the uncommon and overlapping imaging findings of these lesions, in addition to familiarity with the typical aspects. In this article, we reconfirm the well-known characteristic imaging features of pancreatic cystic lesions and present several diagnostically challenging cases, focusing on the uncommon and overlapping imaging findings.

Validation of the clinical utility of 4 guidelines in the initial triage of mucinous cystic lesions of the pancreas based on cross-sectional imaging: Experience with 188 surgically-treated patients

INTRODUCTION

Over the years, several guidelines have been introduced to guide management of mucinous pancreatic cystic neoplasms (mPCN). In this study, we aimed to evaluate and compare the clinically utility of the Sendai-06, Fukuoka-12, Fukuoka-17 and European-18 guidelines in predicting malignancy of mPCN.

METHODS

One hundred and eighty-eight patients with mucinous cystic neoplasms (MCN) or intraductal papillary mucinous neoplasm (IPMN) who underwent surgery were retrospectively reviewed and classified under the 4 guidelines. Malignancy was defined as high grade dysplasia and invasive carcinoma.

RESULTS

Raised CA19-9>37U/ml, enhancing mural nodule≥5 mm and main pancreatic duct≥10 mm were significantly associated with malignancy on multivariate analysis. Increasing number of high risk features, absolute indications (European-18), worrisome risk or relative indications (European-18) were significantly associated with an increased likelihood of malignancy. The positive predictive values (PPV) of high risk features for Sendai-06, Fukuoka-12, Fukuoka-17 and absolute indications (European-18) for malignancy were 53%, 76%, 78% and 78% respectively. The negative predictive values (NPV) of the Sendai-06, Fukuoka-12 and Fukuoka-17 were 100%, while that of the European-18 was 92%. Risk of malignancy for patients with ≥4 worrisome features (Fukuoka-17) and ≥3 relative indications (European-18) was 66.7% and 75.0% respectively.

CONCLUSIONS

All 4 guidelines studied were useful in the initial triage of mPCN for the risk stratification of malignancy. The Fukuoka-17 had the highest PPV and NPV.

Mucinous Cystic Neoplasm of the Liver and Extrahepatic Biliary Tract with Ascending Cholangitis: a Case Report and Review of the Literature

Mucinous cystic neoplasms of the liver involving the extrahepatic biliary tract is a rare slow-growing benign neoplasm of biliary system that has an early clinical presentation with obstructive jaundice. These tumors have a high risk of malignant transformation, which is difficult to diagnose preoperatively by radiology or endoscopy. We present a 31-year-old female patient who presented with complaints of pain abdomen, vomiting, fever, and obstructive jaundice. Ultrasound abdomen showed features suggestive of cholangitic abscess. Computed tomography abdomen showed features suggestive of cholangitic abscess and abrupt termination of the proximal CBD secondary to the stricture. A left hemi-hepatectomy was performed which showed a multiloculated cystic liver lesion with the involvement of extrahepatic duct, cystic duct, and proximal common bile duct. Histopathology showed cyst was lined by mucin secreting columnar epithelium without nuclear atypia, the wall the cysts showed ovarian-like stroma, and the diagnosis of mucinous cystic neoplasms of the liver and extrahepatic biliary tract with ascending cholangitis was made. Regular follow-up by clinical and radiological examination at 6 months did not reveal any recurrence.

Molecular Diagnosis of Cystic Neoplasms of the Pancreas: a Review

BACKGROUND

The prevalence of incidental pancreatic cystic neoplasms (PCNs) has increased dramatically with advancements in cross-sectional imaging. Diagnostic imaging is limited in differentiating between benign and malignant PCNs. The aim of this review is to provide an overview of biomarkers that can be used to distinguish PCNs.

METHODS

A review of the literature on molecular diagnosis of cystic neoplasms of the pancreas was performed.

RESULTS

Pancreatic cysts can be categorized into inflammatory and non-inflammatory lesions. Inflammatory cysts include pancreatic pseudocysts. Noninflammatory lesions include both mucinous and non-mucinous lesions. Mucinous lesions include intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm. Non-mucinous lesions include serous cystadenoma and solid-pseudopapillary tumor of the pancreas. Imaging, cyst aspiration, and histologic findings, as well as carcinoembryonic antigen and amylase are commonly used to distinguish between cyst types. However, molecular techniques to detect differences in genetic mutations, protein expression, glycoproteomics, and metabolomic profiling are important developments in distinguishing between cyst types.

DISCUSSION

Nomograms incorporating common clinical, laboratory, and imaging findings have been developed in a better effort to predict malignant IPMN. The incorporation of top molecular biomarker candidates to nomograms may improve the predictive ability of current models to more accurately diagnose malignant PCNs.

Preoperative differentiation of pancreatic mucinous cystic neoplasm from macrocystic serous cystic adenoma using radiomics: Preliminary findings and comparison with radiological model

PURPOSE

To develop a radiomics model in the preoperative differentiation of mucinous cystic neoplasm (MCN) and macrocystic serous cystadenoma (MaSCA) and to compare its diagnostic performance with conventional radiological model.

METHODS

57 Patients (MCN = 31, MaSCA = 26) with preoperative multidetector computed tomography (MDCT) scans were retrospectively included in this study. A radiological model was constructed from radiological features evaluated by radiologists. A radiomics model was constructed with high-dimensional quantitative features extracted from manually segmented volume of interests (VOIs). A combined model was constructed using both radiomics features and radiological features. The diagnostic performance of three models were assessed by the area under the receiver-operating characteristic curve (AUC), sensitivity, specificity, accuracy, and the calibration curves.

RESULTS

The radiological model yielded an AUC of 0.775, sensitivity of 74.2 %, specificity of 80.8, and accuracy of 77.2 %. The radiomics model yielded an AUC of 0.989, sensitivity of 93.6 %, specificity of 96.2 %, and accuracy of 94.7 %. The combined model yielded an AUC of 0.994, sensitivity of 96.8 %, specificity of 100 %, and accuracy of 98.2 %. Both combined model and radiomics model showed higher AUC, sensitivity, and accuracy than radiological model (all P <  .05). The combined model showed higher AUC than radiomics model, though no significant difference was found (P =  .41). The combined model showed better calibration than radiomics model (P =  .91 vs. P <  .001).

CONCLUSIONS

Combined model which contained both radiomics features and radiological features outperformed radiomics model and radiological model in the preoperative differentiation of MCN and MaSCA.

Diffuse histology-proven mucinous cystic neoplasm of the pancreas: A case report and review of literature

INTRODUCTION

Mucinous cystic neoplasms (MCN) are rare premalignant neoplasms of the pancreas that are typically found as single lesions in the pancreatic body and tail of women in the fifth and sixth decade of life, do not communicate with the pancreatic ductal system and are characterized by mucin-producing epithelium supported by ovarian-type stroma.

PRESENTATION OF CASE

We present here a case of diffuse pancreatic involvement by MCN in a 64-year-old woman with chronic pancreatitis. Pre-operative suspicion for MCN was low due to the multi-centric nature of the lesions and imaging/biochemical fluid analysis demonstrating connection with the pancreatic ductal architecture. The patient underwent total pancreatectomy with pathology showing multiple cysts lined by flat epithelium with focal ovarian-type stroma, consistent with low-grade MCN.

DISCUSSION

The presence of ovarian stroma on histological analysis is one of the defining characteristics of MCNs per WHO guidelines, and is mandatory for its diagnosis. Only one case of diffuse MCN has been previously described in the literature; however, in this case the authors were not able to reach a definitive histological diagnosis based on WHO criteria.

CONCLUSION

To our knowledge, this is the first report of diffuse histology-proven MCN of the pancreas.

Laparoscopic excision of a retroperitoneal mucinous cystic neoplasm: A case report

•

Primary retroperitoneal mucinous cystic neoplasms are rare.

•

Due to potential seeding intra-operatively, laparoscopic removal was avoided.

•

Our case showed efficient and safe use of a laparoscopic approach.

•

Surgeons must plan for every cyst to be malignant when planning for removal.

•

With a laparoscopic approach, care is required when aspirating the cyst in vivo.

Introduction

A 22-year-old female presented with a large abdominal mass that was revealed to be a primary retroperitoneal mucinous cystadenoma.

Presentation of Case

A 22-year-old female presented with a two day history of bloating, mid-epigastric pain, and nausea without vomiting. A CT scan of her abdomen/pelvis showed a large left retroperitoneal mass, possibly a mesenteric cyst. The patient underwent laparoscopic surgery for mass excision. Once the cystic mass was completely dissected laparoscopically, it was placed in a large endobag. The fluid was then aspirated while in the bag to decompress and then completely taken out through a port site. She was discharged the following day. Final pathology revealed a benign mucinous cystadenoma/cystadenofibroma of mesenteric origin.

Discussion

Primary retroperitoneal mucinous cysts are rare occurrences and benign mucinous cystadenomas are the rarest subtype. We use an innovative laparoscopic technique with complete excision of the cyst without spillage of content, thus preventing possible seeding in case of malignancy.

Conclusion

There is some previous caution in using a laparoscopic approach for cystic masses due to potential seeding intra-operatively, in case of fluid spillage of a possible malignant neoplasm. We show through our case that it is possible to efficiently and safely use such an approach.

Two cases of non-mucinous cystadenomas of the pancreas with pancreatobiliary phenotype and ovarian-like stroma

BACKGROUND

Diagnosis of cystic tumor of the pancreas is based on the World Health Organization criteria that classify pancreatic cystadenomas into four types: intra-ductal papillary mucinous neoplasms, mucinous cystic neoplasms (MCNs), serous cystic neoplasms, and solid pseudo-papillary neoplasms depending on their secretion and presence of ovarian-like stroma. Recently, Albores-Saavedra identified non-mucinous cystadenomas of the pancreas with pancreato-biliary phenotype and ovarian-like stroma. This precipitated examination of the proportions of these rare tumors in patients treated at Tokushima University Hospital.

CASE PRESENTATION

Case 1 was a 40-year-old woman with a cystic tumor in the tail of the pancreas. Computed tomography (CT) revealed a diffuse and non-enhanced cystic tumor in the tail of the pancreas. This tumor was diagnosed as a simple cyst at this point. However, 2 years later, the tumor had increased in size by 3 cm. Thus, laparoscopic distal pancreatectomy was performed. The content of the cyst was serous. The epithelial cells were lined with a single layer of cuboidal cells and the tumor had ovarian-like stroma pathologically. The final pathological diagnosis was non-mucinous cystadenoma of the pancreas with ovarian-like stroma. In Case 2, a cystic tumor in the pancreas was found by medical examination in a woman in her sixties who presented without symptoms. CT showed a 1.5-cm cystic tumor in the tail and body of the pancreas and a septum in the cyst. Nine years later, the tumor had grown to 2.4 cm in diameter and had a clear septum in the cyst. This tumor was diagnosed preoperatively as MCN. Thus, laparoscopic distal pancreatectomy was performed. The cyst contained serous fluid. Microscopic examination showed no ovarian-like stroma and the epithelial cells were lined by a single layer of cuboidal cells. The final pathological diagnosis was non-mucinous cystadenoma of the pancreas with ovarian-like stroma.

CONCLUSIONS

Accurate preoperative diagnosis of this type of pancreatic cystic tumor may be difficult, although it occurs more often than expected. Non-mucinous cystadenomas of the pancreas with ovarian-like stroma need to be considered as a differential diagnosis.

A prospective study on endoscopic ultrasound for the differential diagnosis of serous cystic neoplasms and mucinous cystic neoplasms

Background

To provide criteria for the differential diagnosis of serous cystic neoplasms (SCNs) and mucinous cystic neoplasms (MCNs) by analyzing the imaging features of these two neoplasms by endoscopic ultrasound (EUS).

Methods

From April 2015 to December 2017, a total of 69 patients were enrolled in this study. All patients were confirmed to have MCNs (31 patients) or SCNs (38 patients) by surgical pathology. All patients underwent EUS examination. The observation and recorded items were size, location, shape, cystic wall thickness, number of septa, and solid components.

Results

Head/neck location, lobulated shape, thin wall and > 2 septa were the specific imaging features for the diagnosis of SCNs. When any two imaging features were combined, we achieved the highest area under the curve (Az) (0.824), as well as the appropriate sensitivity (84.2%), specificity (80.6%), positive predictive value (PPV) (84.2%), and negative predictive value (NPV) (80.6%). Body/tail location, round shape, thick wall and 0–2 septa were the specific imaging features for the diagnosis of MCNs. When any three imaging features were combined, we obtained the highest Az value (0.808), as well as the appropriate sensitivity (77.4%), specificity (84.2%), PPV (80.0%) and NPV (82.1%).

Conclusions

Pancreatic cystadenomas that meet any two of the four imaging features of head/neck location, lobulated shape, thin wall and > 2 septa could be diagnosed as SCNs, and those that meet any three of the four imaging features of body/tail location, round shape, thick wall and 0–2 septa could be considered as MCNs.

Trial registration

The study was registered at the Chinese Clinical Trial Registry. The registration identification number is ChiCTR-OOC-15006118. The date of registration is 2015-03-20.

Mucinous cystic neoplasm of the pancreas assessed with a real-time three-dimensional imaging using a transesophageal echocardiography probe

Ultrasonographic imaging techniques have been rapidly developing. The new transesophageal echocardiography (TEE) system made it possible to obtain the real-time three-dimensional (3D) image of the cardiac system through the esophagus, that can be applied to the field of gastroenterology. We herein present a case of 72-year-old woman who was referred for evaluation of an incidentally found cystic lesion in the tail of the pancreas. The real-time 3D imaging with TEE probe clearly demonstrated the internal features of the cyst consistent with MCN, which helped narrow down the differential diagnosis. The patient was proceeded with distal pancreatectomy and a definite diagnosis of MCN was confirmed with the histopathological findings of the resected specimen associated with ovarian-type stroma. This is the first report which showed the real-time 3D image of MCN in the pancreas obtained with TEE. Further investigation is warranted to determine the clinical relevance of 3D ultrasonographic techniques used to evaluate the pancreatic cystic lesions.

Pancreatic Cysts: Sinister Findings or Incidentalomas?

Pancreatic cysts are common and are incidentally detected in up to 13.5% of individuals. Intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN) are precursors to pancreatic adenocarcinoma. Most will never develop into pancreatic cancer. Several types of pancreatic cysts have no malignant potential. Solid tumors can present as a pancreatic cysts. Guidelines recommend surveillance. Management includes differentiating IPMNs and MCNs from other types, identifying those at highest risk of harboring pancreatic cancer or high-grade dysplasia, and referral to a multidisciplinary group for evaluation and consideration of surgical resection.

Histo-molecular oncogenesis of pancreatic cancer: From precancerous lesions to invasive ductal adenocarcinoma

Pancreatic cancer is a lethal malignancy, whose precursor lesions are pancreatic intraepithelial neoplasm, intraductal papillary mucinous neoplasm, intraductal tubulopapillary neoplasm, and mucinous cystic neoplasm. To better understand the biology of pancreatic cancer, it is fundamental to know its precursors and to study the mechanisms of carcinogenesis. Each of these precursors displays peculiar histological features, as well as specific molecular alterations. Starting from such pre-invasive lesions, this review aims at summarizing the most important aspects of carcinogenesis of pancreatic cancer, with a specific focus on the recent advances and the future perspectives of the research on this lethal tumor type.

Familial Pancreatic Cancer

Familial pancreatic cancer accounts for 10% of all patients with pancreatic cancer. Because the 5-year survival rate of pancreatic cancer is only 7%, screening programs for high-risk individuals are essential and might be advantageous. Pancreatic ductal adenocarcinoma mostly shows symptoms at an advanced state and treatment is not efficient enough to cure most patients. People with hereditary tumor syndromes or their affected relatives can also be included in such screening programs. Besides the collection of data to investigate the background of the disease, these screening programs aim to diagnose and treat precursor lesions so that more dangerous, invasive lesions are prevented. These precursor lesions can be pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. This review summarizes the latest knowledge of pancreatic screening programs, shows the procedure of pancreatic cancer screening, and gives an overview of current guidelines.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

Cyst Fluid Biomarkers - Diagnosis and Prediction of Malignancy for Cystic Lesions of the Pancreas

Pancreatic cysts are common, and are identified in 2-13% of individuals undergoing cross-sectional imaging. Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are pancreatic cysts which are precursors to pancreatic adenocarcinoma. Currently available tools are imperfect at differentiating IPMNs and MCNs from other, benign types of pancreatic cysts. The role of molecular markers in the evaluation of pancreatic cysts and the identification of cysts with high-grade dysplasia or invasive adenocarcinoma is reviewed.

The Role of Endoscopic Ultrasound in the Diagnosis of Cystic Lesions of the Pancreas

A precise diagnosis of the nature of pancreatic cystic neoplasm (PCN) is crucial since it determines the patients in need of rapid surgical resection as well as those who can be followed up, and, accordingly, the frequency and modalities of surveillance. Endoscopic ultrasound (EUS) and especially fine needle aspiration (FNA) are invasive methods, with specific adverse events occurring in 2.7-5%. Thus, they should only be used as a third-line tool in the absence of characteristic radiographic features on computed tomography (CT) scan and magnetic resonance imaging (MRI). The most difficult aspects of differential diagnosis are: intraductal papillary mucinous neoplasm (IPMN) versus chronic pancreatitis; unifocal IPMN versus serous cystic neoplasm (SCN); macrocystic SCN versus mucinous cystic neoplasm (MCN); cystic neuroendocrine tumors versus MCN; solid serous cystadenoma versus neuroendocrine tumors versus small solid pseudopapillary tumors; pseudocyst versus MCN; low-grade, high-grade, or invasive IPMN. When classical radiological and EUS features are not conclusive, EUS-FNA may be helpful by analyzing cytological, chemical, and/or molecular data. The addition of EUS-FNA to CT scan and MRI increased the overall accuracy for diagnosing PCN by 36 and 54%, respectively. Analysis of molecular markers in pancreatic cyst fluid might increase the limited accuracy of EUS-FNA by using cytology and chemical and/or tumor marker analysis alone. Current evidence suggests that contrast-enhanced EUS (CH-EUS) is highly accurate for distinguishing non-neoplastic cysts from neoplastic cysts. CH-EUS might also be useful for distinguishing mural epithelial nodules from mucinous clots. Needle-based confocal laser endomicroscopy (nCLE) images a target tissue at a subcellular level of resolution, providing real-time in-vivo optical biopsy. nCLE is feasible during EUS-FNA and allows in-vivo diagnosis of PCN with high accuracy. In conclusion, EUS is a third-line tool in the diagnosis of PCN. Clinical context as well as careful evaluation of CT scan and magnetic resonance cholangiopancreatography images by specialized radiologists are crucial in the diagnosis process. Nowadays it is inconceivable to skip these steps.

Mucinous cystic neoplasms of the pancreas: high-resolution cross-sectional imaging features with clinico-pathologic correlation

PURPOSE

To describe the high-resolution cross-sectional (MDCT/MRI) features of mucinous cystic neoplasms (MCN) of the pancreas with clinico-pathologic correlation; to identify imaging predictors of high-grade dysplasia/carcinoma; and to estimate MCN growth rate.

MATERIALS AND METHODS

Thirty-two women (mean age: 46; range, 25-79 years) with resected MCN who underwent preoperative MDCT (n = 20) or MRI (n = 12) examinations over a 14-year period were included. Two radiologists examined retrospectively in consensus the following MDCT/MRI features: MCN location, size/volume, presence of capsule and thickness of the capsule, and presence of mural nodules, enhancing septations, calcifications, chronic pancreatitis, and main pancreatic duct dilation. Imaging features were correlated with clinical symptoms, biochemistry results, and histopathologic features. A univariate model was analyzed for the prediction of high-grade dysplasia/carcinoma. Preoperative MCN growth rate was assessed using a subset of patients with more than one imaging study available (n = 6).

RESULTS

Twenty-five (78%) patients presented with symptoms and 8 (25%) patients had abnormal serum biochemical values. Mean MCN maximum dimensions were 48 × 45 × 45 mm with a mean volume of 169 mL. MCN were located in the tail (n = 18), body (n = 10), neck (n = 2), and (head = 2); 30 (93.5%) MCN were encapsulated, 3 (9%) had calcifications, 4 (12%) showed enhancing nodules, 9 (28%) had enhancing septations, and 5 (15%) had main pancreatic duct dilation. Associated chronic pancreatitis was observed in 4 (12%) patients. The only predictors for high-grade dysplasia/carcinoma were MCN size and volume. Using a cut-off size greater than 8.5 cm, the specificity and sensitivity for high-grade dysplasia/carcinoma were 97 and 60%, respectively (p = 0.003; OR 81, 95% CI 3.9-1655.8). Mean MCN growth rate was estimated at 4.2 mm/year with a doubling time of 8.23 years.

CONCLUSION

MCN size (> 8.5 cm) and volume are the only features on MDCT/MR imaging that correlate with high-grade dysplasia/carcinoma. The average growth rate for MCNs is slow at approximately 4 mm per year.

Pure Laparoscopic Transhepatic Enucleation of a Mucinous Cystic Neoplasm Abutting the Major Hepatic Veins at the Hepatocaval Confluence (with Video)

BACKGROUND

A mucinous cystic neoplasm (MCN) of the liver is a rare disease entity, occurring predominantly in the left hemiliver as reported by Simo et al.1 Thomas et al.2 and Vogt et al.3 Surgical resection of tumors at the hepatocaval confluence is a technically demanding procedure. Enucleation procedures have been performed for the management of benign or premalignant lesions such as cystic tumors as previously described by Thomas et al.2 and Vogt et al.3. We present a patient who underwent pure laparoscopic transhepatic enucleation to treat a MCN abutting the major hepatic veins at the hepatocaval confluence.

METHODS

We treated a 77-year-old man who presented with a 5-cm-sized cystic mass at the hepatocaval confluence. Using the Pringle maneuver, we performed liver parenchymal transection along the junction between the origin of the middle hepatic vein (MHV) and the inferior vena cava (IVC) as reported by Kim4. The MHV formed the left-sided boundary of the cystic mass. After dissection of the left boundary of the cystic wall, the dorsal side of the cystic mass was carefully dissected. Liver parenchymal transection was continued up to the right hepatic vein (RHV). Laparoscopic enucleation was performed to expose the RHV and MHV, as well as the IVC.

RESULTS

The operation time was 270 min, the estimated blood loss was 80 mL, and no transfusion was necessary in this patient. The final histopathological diagnosis of the mass was MCN. Postoperatively, the patient recovered uneventfully, and he was discharged on postoperative day 5.

CONCLUSIONS

Laparoscopic transhepatic enucleation for MCNs at the hepatocaval confluence is technically feasible and offers the benefits of a parenchyma-sparing resection. However, this procedure requires a high level of technical skills and shows a steep learning curve.

[Simple mucinous cyst of the pancreas: Case-report and literature review]

Simple mucinous cyst of the pancreas is an unusual pancreatic cyst, first described by Kosmahl et al. in 2002 with 5 cases. We describe a case of simple mucinous cyst of the pancreas, followed by a literature review. The physiopathology of this cyst is still unclear. It is an epithelial cyst, presenting as unilocular cystic lesion of the pancreatic body or tail, with a clear content, and no communication with the pancreatic duct. Microscopically, the cyst is lined by mucin-producing cells with mild atypia, and contains a fibrous wall without ovarian-like stroma. The prognosis is excellent, as no recurrent disease and progression to malignancy have been described. The non neoplastic origin of this lesion is debated, as cases with KRAS mutation and intra-epithelial neoplastic lesions have been recently reported. It is important to distinguish this lesion from macrocystic serous cystadenoma, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, by clinical, radiological and pathological features, as the treatment varies from simple surveillance to surgical resection.

Prevalence and outcomes of pancreatic cystic neoplasms in liver transplant recipients

AIM

To determine the prevalence, characteristics and clinical course of pancreatic cystic neoplasms (PCNs) in liver transplantation (LT) recipients.

METHODS

We retrospectively studied consecutive patients who underwent LT between January 1998 to April 2016. Clinical and laboratory data were obtained from patient medical records. Imaging findings on computed tomography and magnetic resonance cholangiopancreatography were reviewed by two radiologists.

RESULTS

During the study period, 872 patients underwent cadaveric LT. Pancreatic cysts were identified in 53/872 (6.1%) and 31/53 (58.5%) were PCNs [28 intraductal papillary mucinous neoplasm (IPMN), 2 mucinous cystic neoplasm (MCN), 1 serous cystadenoma]. Patients with PCNs exhibited less male predominance (55% vs 73%, P = 0.03) compared to patients without pancreatic cysts. Thirteen patients (42%) were diagnosed with PCN pre-LT while 18 patients (58%) developed PCN post-LT. The median size of PCNs was 13mm [interquartile range (IQR) 10-20 mm]. All IPMNs were side-branch type. Most PCNs were found in the head and body of pancreas (37% each), followed by the tail (25%). Five patients underwent further evaluation with endoscopic ultrasound. Progress imaging was performed on 81% of patients. PCNs remained stable in size and number in all but 2 patients. During a median follow up of 39 mo (IQR 26-58 mo), the 2 (6%) patients with MCN underwent pancreatectomy. No PCN patient developed pancreatic adenocarcinoma, while 5 died from illnesses unrelated to the PCN. Among patients without PCN, 1/841 (0.1%) developed pancreatic adenocarcinoma.

CONCLUSION

The prevalence of PCNs in LT recipients was similar to the general population (3.6%, 31/872). Side-branch IPMNs do not appear to have accelerated malignant potential in post-LT patients, indicating the current surveillance guidelines are applicable to this group.

Mucinous Cystic Neoplasms Lined by Abundant Mucinous Epithelium Frequently Involve KRAS Mutations and Malignant Progression

BACKGROUND

Pancreatic and hepatic mucinous cyst neoplasms (MCNs) have a malignant potential, but indolent MCNs are not uncommon.

MATERIALS AND METHODS

The pathological and genetic characteristics of resected MCNs (n=15) categorized by the amount of mucin of the lining epithelium were investigated.

RESULTS

MCNs were divided into two groups: (i) a rich (r)-MCN group (n=6), in which more than half of the epithelium was lined by abundant mucinous epithelium; and (ii) a poor (p)-MCN group (n=9), which consisted of the remaining cases. Three patients in the r-MCN group showed invasive carcinoma or high-grade dysplasia, whereas all patients in the p-MCN group showed low-grade dysplasia. Mutations of Kirsten rat sarcoma viral oncogene homolog (KRAS) were more frequent in the r-MCN group (83%) (p-MCN; 11%, p<0.05).

CONCLUSION

Mucinous MCNs more frequently have KRAS mutations and higher risk of malignant progression.

Endoscopic Ultrasound Imaging for Diagnosing and Treating Pancreatic Cysts

Cystic pancreatic lesions are increasingly diagnosed owing to the abundant use of cross-sectional imaging. Given their malignant potential, true pancreatic cysts should be considered for resection or periodic follow-up. Cystic lesions of the pancreas (CLPs) require further evaluation and management. Therefore, it is important to establish a solid diagnosis at the time of detection. Endoscopic ultrasound examination is the imaging modality of choice. Fine needle aspiration provides fluid for cytologic, biochemical, and molecular assays to classify lesions and predict biological behavior. This review provides an overview of the diagnosis and management of various types of commonly encountered true CLPs.

Molecular Diagnostics in the Evaluation of Pancreatic Cysts. Surg Pathol Clin. 2016;9:441-456. [PMID: 27523971 DOI: 10.1016/j.path.2016.04.008]

Within the past few decades, there has been a dramatic increase in the detection of incidental pancreatic cysts. It is reported a pancreatic cyst is identified in up to 2.6% of abdominal scans. Many of these cysts, including serous cystadenomas and pseudocysts, are benign and can be monitored clinically. In contrast, mucinous cysts, which include intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, have the potential to progress to pancreatic adenocarcinoma. In this review, we discuss the current management guidelines for pancreatic cysts, their underlying genetics, and the integration of molecular testing in cyst classification and prognostication.

Comparison between MRI with MR cholangiopancreatography and endoscopic ultrasonography for differentiating malignant from benign mucinous neoplasms of the pancreas

OBJECTIVE

To compare diagnostic performance of magnetic resonance imaging (MRI) and endoscopic ultrasonography (EUS) for differentiating malignant from benign intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms (MCN) of the pancreas.

METHODS

This retrospective study included 55 patients with 47 surgically confirmed IPMNs (12 malignant, 35 benign) and eight MCNs (two malignant, six benign) who underwent contrast-enhanced pancreas MRI and EUS. Contrast enhancement was not routinely used at EUS examination. Two observers independently evaluated the MRIs, and another reviewed EUS images. They recorded their confidence for malignancy with each imaging modality. We calculated diagnostic performance using the area under the receiver operating characteristic curves (A _z ), and to determine the accuracy, sensitivity, specificity, and positive (PPV) and negative predictive (NPV) values.

RESULTS

The A _z values of MRI were higher than those of EUS (0.712 and 0.688 for MRI vs. 0.543 for EUS; p = 0.007). The diagnostic accuracies (74.5%), specificity (78.0% and 80.5%) and PPV (50.0%) of MRI in two observers were higher than those (56.4%, 58.5% and 29.2%, respectively) of EUS (p = 0.013-0.049).

CONCLUSION

MRI showed better diagnostic performance than EUS for differentiating malignant from benign pancreatic IPMN and MCN.

KEY POINTS

• The A _z values of MRI were higher than those of EUS. • The diagnostic accuracies of MRI were higher than those of EUS. • The specificities of MRI were higher than those of EUS.

Laparoscopic left hepatectomy for mucinous cystic neoplasm of the liver

BACKGROUND

Among liver cystic lesions, mucinous cystic neoplasm of the liver (MCN-L) constitutes a challenging issue in terms of management: preoperative diagnosis is often unachievable and this may mislead to inappropriate treatment [1-3]. We present the case of an otherwise healthy 29-year-old female who underwent laparotomic cyst unroofing in segment 4 and cholecystectomy in another institution. Post-operative course was complicated by biliary leakage that was endoscopically treated. Short term follow-up showed early recurrence with a volumetric enlargement of the cyst occupying most of the left hepatic lobe and new satellite cyst in Sg5. The doubt of MCN-L arose, and the patient was scheduled for laparoscopic removal at our Centre, despite the previous laparotomic procedure.

METHODS

An optic port was placed into right upper abdominal quadrant and 3 further ports were placed. A long and difficult adhesiolysis was performed and Pringle's manoeuver was settled. Intraoperative US confirmed the anatomic limits of the cysts in Sg5 and in the left hepatic lobe. The cyst on Sg5 was resected first and frozen section was suspicious for MCN-L. In order to prevent recurrence, left laparoscopic hepatectomy was performed. The specimen was extracted through the previous midline laparotomy.

RESULTS

Post-operative course was uneventful and the patient was discharged on POD 5. Pathology and immunochemistry confirmed the diagnosis of MCN-L.

CONCLUSION

Hepatic cystic lesions may be insidious and preoperative biopsy is not always possible due to lack of solid tissue. In unclear settings, an intraoperative frozen section is mandatory to guide intraoperative decisions. In the suspicion of malignancy, resection with oncologic criteria must be chosen as the most appropriate treatment, as well as the retrieving of MCN-L requires hepatic resection to avoid early recurrence [4, 5]. Despite of previous laparotomy, we consider a laparoscopic approach could be attempted in selected cases, in institution with particular expertise in laparoscopic liver surgery.

Pancreatic cancer screening: Still a delusion?

Pancreatic adenocarcinoma represents the fourth most common cause of cancer mortality and death due to pancreatic cancer (PC) have increased since 2003. Its incidence has also raised about 30% in the past decade and it is expected to become the second cause of cancer mortality by 2020 in the USA. Most PC present with metastatic disease and improvements in treatment outcomes for this group have been disappointing. These observations support the idea that screening to identify patients at an earlier stage might be an important strategy in improving overall PC outcomes. Many protocols have been tested, nevertheless, by now there is no effective screening program. Given the overall low incidence of disease and the current lack of accurate, inexpensive and noninvasive screening tests, the consensus is that widespread population-based screening for PC in the general population or in patients with only one affected first-degree relative is neither practicable nor indicated in most countries. However, a different scenario is screening patients with higher risk for PC, most of them with hereditary conditions predisposing the development of this neoplasia. In fact, some guidelines are now available helping to select these individuals at risk and to screen them, in order to achieve early detection of PC.

Novel Biomarkers for Pancreatic Cysts

With increased utilization and ongoing advancements in cross-sectional abdominal imaging, the identification of a pancreatic cyst has become a frequent finding. While many pancreatic cysts are associated with a benign clinical course, others may transform into pancreatic ductal adenocarcinoma. However, distinguishing a benign from a malignant pancreatic cyst or pancreatic cyst with malignant potential on the basis of standard clinical findings, imaging parameters and ancillary studies can be challenging. Hence, a significant interest within the past decade has been the identification of novel biomarkers to accurately classify and prognosticate a pancreatic cyst. Within this review, we discuss novel DNA, miRNA, protein and metabolite biomarkers, and their relevance in clinical practice. In addition, we focus on future areas of research that have the potential to change pancreatic cyst management.

Insights into the Pathogenesis of Pancreatic Cystic Neoplasms

With the current epidemic of diagnosed pancreatic cystic neoplasms on the rise, a substantial amount of work has been done to unravel their biology, thus leading to implications on clinical decision making. Recent genetic profiling of resected human specimens has identified alterations in signaling pathways involving KRAS and GNAS signaling as early events in the pathogenesis of intraductal pancreatic mucinous neoplasms. Progressively, mutations in genes such as TP53, SMAD4, RNF43, and others are thought to characterize invasive and advanced lesions. The role of inflammation in fueling the growth and transformation of these cysts has also begun to be studied with greater interest. A number of promising clinical studies have attempted to integrate these genetic insights into classifying these cysts and treating patients. We have reviewed existing literature on similar lines besides commenting on some useful animal models that recapitulate molecular and phenotypic progression of these cysts.