Typical and atypical manifestations of serous cystadenoma of the pancreas: imaging findings with pathologic correlation. AJR Am J Roentgenol. 2009;193:136-142. [PMID: 19542405 DOI: 10.2214/ajr.08.1309]

Diagnosis and Management of Pancreatic Cysts

As pancreatic cyst incidence rises, likely due to the ubiquitous increase in cross-sectional imaging, their management presents multiple challenges for both the practitioner and patient. It is critical that all pancreatic cysts are appropriately characterized, as treatment decisions depend on an accurate diagnosis. Diagnostic modalities such as cytology, biopsy, and cyst fluid biomarkers allow for definitive diagnosis of virtually all lesions. Some cysts, such as intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and cystic pancreatic endocrine neoplasms, have malignant potential and must be surveyed. Other cysts, such as serous cystadenomas and pancreatic fluid collections, do not have malignant potential. Surveillance strategies vary widely depending on cyst type and size and while multiple medical societies advocate surveillance, their published surveillance guidelines are heterogenous. Cysts with high-risk stigmata or worrisome features are usually resected, depending on the patient's surgical fitness. In patients unfit for resection, newer endoscopic ablative techniques are advocated. Controversial aspects regarding cyst management include whether surveillance can be stopped, how surveillance should be performed, and the extensive financial burden cyst management places on the health care system. Further study into the natural history of cystic lesions, including definitive determination of the rate of malignant transformation for each cyst type, is essential.

Imaging classification of pancreatic ductal adenocarcinoma with histological large duct pattern

OBJECTIVES

To investigate the imaging features of pancreatic ductal adenocarcinoma (PDAC) with histological large duct pattern.

METHODS

Our study included 37 patients (mean age, 66.5 years; 22 women) with surgically proven PDAC with histological large duct pattern, whose imaging features were classified into four types: Type I, solid mass; Type II, predominantly cystic mass with intracystic solid components; Type III, predominantly solid mass with intratumoral cysts; and Type IV, solid mass with peritumoral retention cysts or pseudocysts. Two radiologists independently analyzed both CT and MRI images for the morphological type, presence of abrupt main pancreatic duct (MPD) cutoff, adjacent vascular invasion, diffusion restriction, and reached consensus.

RESULTS

On CT, 26 patients (70.3%) had Type I tumors, five (13.5%) had Type II, three (8.1%) had Type III, and three (8.1%) had Type IV. Among the 26 patients with Type I tumors on CT, 16 had tumors with multiple intratumoral cysts within the solid mass on MRI and were subsequently classified as Type III. Accordingly, 10 patients (27.0%) were classified as Type I, five (13.5%) as Type II, 19 (51.7%) as Type III, and three (8.1%) as Type IV on MRI. Of the 37 patients, 27 (73.0%) had an abrupt MPD cutoff, 15 (40.5%) had adjacent vascular invasion, and 25 (67.6%) had diffusion restriction on MRI.

CONCLUSIONS

Predominantly solid pancreatic masses with small intratumoral cysts visualized on MRI may be a characteristic imaging finding of PDAC with histological large duct pattern, and differentiate it from conventional PDAC or other cystic pancreatic tumors.

CLINICAL RELEVANCE STATEMENT

Radiologists should be familiar with the various imaging features of PDAC with histological large duct pattern and should be aware that it may mimic other solid or cystic tumors of the pancreas.

KEY POINTS

Imaging features of pancreatic ductal adenocarcinoma with histological large duct pattern can be classified into four types. This pathology more frequently appears as a predominantly solid mass with intratumoral cysts on MRI than on CT. Adding MRI to CT may help identify pancreatic ductal adenocarcinoma with histological large duct pattern.

Utilization of texture features of volumetric ADC maps in differentiating between serous cystadenoma and intraductal papillary neoplasms

INTRODUCTION

The rising incidence of incidental detection of pancreatic cystic neoplasms has compelled radiologists to determine new diagnostic methods for the differentiation of various kinds of lesions. We aim to demonstrate the utility of texture features extracted from ADC maps in differentiating intraductal papillary mucinous neoplasms (IPMN) from serous cystadenomas (SCA).

METHODS

This retrospective study was performed on 136 patients (IPMN = 87, SCA = 49) split into testing and training datasets. A total of 851 radiomics features were extracted from volumetric contours drawn by an expert radiologist on ADC maps of the lesions. LASSO regression analysis was used to determine the most predictive set of features and a radiomics score was developed based on their respective coefficients. A hyper-optimized support vector machine was then utilized to classify the lesions based on their radiomics score.

RESULTS

A total of four Wavelet features (LHL/GLCM/LCM2, HLL/GLCM/LCM2, /LLL/First Order/90percent, /LLL/GLCM/MCC) were selected from all of the features to be included in our classifier. The classifier was optimized by altering hyperparameters and the trained model was applied to the validation dataset. The model achieved a sensitivity of 92.8, specificity of 90%, and an AUC of 0.97 in the training data set, and a sensitivity of 83.3%, specificity of 66.7%, and AUC of 0.90 in the testing dataset.

CONCLUSION

A support vector machine model trained and validated on volumetric texture features extracted from ADC maps showed the possible beneficence of these features in differentiating IPMNs from SCAs. These results are in line with previous regarding the role of ADC maps in classifying cystic lesions and offers new evidence regarding the role of texture features in differentiation of potentially neoplastic and benign lesions.

Pancreatic Cysts: Radiology

This article reviews the types of pancreatic cysts encountered in Radiologic practice. It summarizes the malignancy risk of each of the following: serous cystadenoma, mucinous cystic tumor, intraductal papillary mucinous neoplasm main duct and side branch, and some miscellaneous cysts such as neuroendocrine tumor and solid pseudopapillary epithelial neoplasm. Specific reporting recommendations are given. The choice between radiology follow-up versus endoscopic analysis is discussed.

Pancreatic Cystic Lesions: Imaging Techniques and Diagnostic Features

The detection of incidental pancreatic cystic lesions has increased over time. It is crucial to separate benign from potentially malignant or malignant lesions to guide management and reduce morbidity and mortality. The key imaging features used to fully characterize cystic lesions are optimally assessed by contrast-enhanced magnetic resonance imaging/magnetic resonance cholangiopancreatography, with pancreas protocol computed tomography offering a complementary role. While some imaging features have high specificity for a particular diagnosis, overlapping imaging features between diagnoses may require further investigation with follow-up diagnostic imaging or tissue sampling.

A Unicorn Disease: The Large Duct Variant of Invasive Ductal Adenocarcinoma of the Pancreas

Large duct adenocarcinoma (LDA) is a rare histopathological variant of pancreatic ductal adenocarcinoma (PDAC) that closely mimics intraductal papillary mucinous neoplasm (IPMN). We present a 74-year-old female diagnosed with LDA in 2017. She was initially managed with chemotherapy and laparoscopic distal pancreatectomy. After five years of stable disease on systemic chemotherapy, she was referred to us to explore further definitive treatments. We used a multidisciplinary approach with curative-intent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC), followed by oral maintenance chemotherapy. Subsequent scans showed stable disease; she eventually underwent neoadjuvant radiation and surgery with intraoperative radiation therapy (IORT) and achieved remission.

The Role of Magnetic Resonance Imaging (MRI) in the Diagnosis of Pancreatic Cystic Lesions (PCLs)

Pancreatic cystic lesions (PCLs) are a common incidental finding on cross-sectional imaging. Given the high signal to noise and contrast resolution, multi-parametric capability and lack of ionizing radiation, magnetic resonance imaging (MRI) has become the non-invasive method of choice to predict cyst type, risk stratify the presence of neoplasia, and monitor changes during surveillance. In many patients with PCLs, the combination of MRI and the patient's history and demographics will suffice to stratify lesions and guide treatment decisions. In other patients, especially those with worrisome or high-risk features, a multimodal diagnostic approach that includes endoscopic ultrasound (EUS) with fluid analysis, digital pathomics, and/or molecular analysis is often necessary to decide on management options. The application of radiomics and artificial intelligence in MRI may improve the ability to non-invasively stratify PCLs and better guide treatment decisions. This review will summarize the evidence on the evolution of MRI for PCLs, the prevalence of PCLs using MRI, and the MRI features to diagnose specific PCL types and early malignancy. We will also describe topics such as the utility of gadolinium and secretin in MRIs of PCLs, the limitations of MRI for PCLs, and future directions.

“Honeycomb” appearance in large-duct type pancreatic ductal adenocarcinoma: Case report with radiologic–pathologic correlation

Large-duct type pancreatic ductal adenocarcinoma (PDA) is a rare morphologic variant forming large duct elements. This case report, to our knowledge, is the first report of a large-duct type PDA with a “honeycomb” appearance resembling a serous cystic neoplasm (SCN) on CT and MRI. The patient is an 82-year-old woman who presented with upper abdominal pain. Dynamic contrast-enhanced CT revealed a multilocular cyst with honeycomb loculi, in which the cyst walls showed gradual enhancement. On T2-weighted MRI, the mass displayed inhomogeneous hyperintensity characterized by a honeycomb appearance with irregular and thick hypointense cyst walls. The patient underwent distal pancreatectomy; histopathological diagnosis was large-duct type PDA. Although the imaging features of large-duct type PDA may resemble those of SCN, this distinction between PDA and SCN is important because the treatment options are very different.

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.

Pancreatic Neoplasms: CT Evaluation of the Uncommon Presentations of Common Lesions and Common Presentations of the Uncommon Lesions!

Pancreatic masses are commonly encountered entities in radiology practice. Pancreatic ductal adenocarcinomas (PDAC) are the commonest pancreatic malignancies that typically present as infiltrative hypodense focal masses in the pancreatic head, which are hypoattenuating to the pancreatic parenchyma on pancreatic parenchymal and venous phases. However, there are various atypical imaging features of PDACs that create a diagnostic dilemma like tumor in body or tail, diffuse glandular involvement, isoattenuating tumors, cystic changes, or calcifications. Also, few relatively uncommon pancreatic malignancies like pancreatic neuroendocrine tumors, cystic pancreatic tumors, pancreatic lymphoma, and pancreatic metastases present with overlapping features. Accurate radiological characterization of pancreatic masses is important for optimal management and prognostication. Thus, it is imperative for radiologists to be aware of all the uncommon presentations of common pancreatic lesions and common presentations of uncommon pancreatic lesions to avoid erroneous interpretations and establishing the correct diagnosis.

Cavernous hemangioma of an intrapancreatic accessory spleen mimicking a pancreatic tumor: A case report

BACKGROUND

Intrapancreatic accessory spleen (IPAS) is an uncommon condition, with the majority of cases presenting as solid lesions. Thus, this condition is frequently misdiagnosed as pancreatic solid neoplasm. Moreover, splenic cavernous hemangioma is a rare disorder, whereas lesions with a cystic appearance arising from IPAS have not been reported.

CASE SUMMARY

Herein, we present a case involving a 32-year-old male who had a complex cystic lesion in the tail of the pancreas revealed by conventional ultrasound. The lesion was misdiagnosed as a pancreatic cystadenoma because of its confusing anatomic location, as well as due to its peripheral nodular and internal septal enhancement patterns on contrast-enhanced ultrasound. After multidisciplinary discussion, the patient finally underwent laparoscopic pancreatic body and tail resections. Postoperative pathology demonstrated the lesion to be a cavernous hemangioma arising from the IPAS.

CONCLUSION

Cavernous hemangioma in the intrapancreatic accessory spleen may mimic pancreatic cystadenoma, which is a condition with the potential to be malignant. Imaging follow-ups or surgical interventions may be helpful for the exclusion of malignant risks in complicated cystic lesions, especially those with parietal and septal enhancements.

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.

Cystic pancreatic lesions: MR imaging findings and management

Cystic pancreatic lesions (CPLs) are frequently casual findings in radiological examinations performed for other reasons in patients with unrelated symptoms. As they require different management according to their histological nature, differential diagnosis is essential. Radiologist plays a key role in the diagnosis and management of these lesions as imaging is able to correctly characterize most of them and thus address to a correct management. The first step for a correct characterization is to look for a communication between the CPLs and the main pancreatic duct, and then, it is essential to evaluate the morphology of the lesions. Age, sex and a history of previous pancreatic pathologies are important information to be used in the differential diagnosis. As some CPLs with different pathologic backgrounds can show the same morphological findings, differential diagnosis can be difficult, and thus, the final diagnosis can require other techniques, such as endoscopic ultrasound, endoscopic ultrasound-fine needle aspiration and endoscopic ultrasound-through the needle biopsy, and multidisciplinary management is important for a correct management.

Cystic lesions of the pancreatico-biliary tree: A schematic MRI approach

Although a common occurrence, cystic lesions of the pancreatico-biliary tree (PBT) may pose a diagnostic dilemma because they encompass a large number of neoplastic and benign processes with varied clinical symptoms. Knowledge of lesion classification and characterization are essential in making an accurate prospective diagnosis. This is necessary for identifying clinically significant cystic masses, which at times may require invasive intervention from indolent, nonneoplastic lesions, for which surveillance may suffice. Today, there is an arsenal of modalities for assessing the PBT, however, magnetic resonance imaging (MRI) remains at the forefront for characterizing cystic morphology and fluid content, internal septations, solid component, enhancement patterns, as well as assessing the surrounding normal structures. This pictorial review aims to review the spectrum of MRI features, which will aid in the differential diagnoses of cystic lesions of the PBT and mimickers, enabling the radiologist to reach a more confident diagnosis.

CT-Based Radiomics Analysis for Preoperative Diagnosis of Pancreatic Mucinous Cystic Neoplasm and Atypical Serous Cystadenomas

Objectives

To investigate the value of CT-based radiomics analysis in preoperatively discriminating pancreatic mucinous cystic neoplasms (MCN) and atypical serous cystadenomas (ASCN).

Methods

A total of 103 MCN and 113 ASCN patients who underwent surgery were retrospectively enrolled. A total of 764 radiomics features were extracted from preoperative CT images. The optimal features were selected by Mann-Whitney U test and minimum redundancy and maximum relevance method. The radiomics score (Rad-score) was then built using random forest algorithm. Radiological/clinical features were also assessed for each patient. Multivariable logistic regression was used to construct a radiological model. The performance of the Rad-score and the radiological model was evaluated using 10-fold cross-validation for area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

Results

Ten screened optimal features were identified and the Rad-score was then built based on them. The radiological model was built based on four radiological/clinical factors. In the 10-fold cross-validation, the Rad-score was proved to be robust and reliable (average AUC: 0.784, sensitivity: 0.847, specificity: 0.745, PPV: 0.767, NPV: 0.849, accuracy: 0.793). The radiological model performed slightly less well in classification (average AUC: average AUC: 0.734 sensitivity: 0.748, specificity: 0.705, PPV: 0.732, NPV: 0.798, accuracy: 0.728.

Conclusions

The CT-based radiomics analysis provided promising performance for preoperatively discriminating MCN from ASCN and showed good potential in improving diagnostic power, which may serve as a novel tool for guiding clinical decision-making for these patients.

Multiparameter Analysis Using 18F-FDG PET/CT in the Differential Diagnosis of Pancreatic Cystic Neoplasms

Purpose

To evaluate multiparametric analysis in differential diagnosis between pancreatic serous cystic neoplasms (SCNs) and mucinous cystic neoplasms (MCNs) as well as the differentiation of the benign and malignant MCNs with ¹⁸F-FDG (18-fluorodeoxyglucose) PET/CT (positron emission tomography).

Methods

Forty patients with total of 41 lesions (SCNs: 27/41; MCNs: 14/41), who were preoperatively examined with ¹⁸F-FDG PET/CT, were retrospectively analyzed. Multiple quantitative parameters using conventional and texture features were included. The combined model was established with complementary PET/MR parameters. The differential diagnostic efficacy of each independent parameter and the combined model were evaluated with receiver operating characteristic (ROC) analysis. Integrated discriminatory improvement (IDI) and net reclassification improvement (NRI) were used to evaluate improvement of diagnostic efficacy by using combination of multiple parameters.

Results

Among all independent parameters, the percentile 5th (0.88 ± 0.38 vs 0.47 ± 0.23, P < 0.001) showed the highest discriminative diagnostic value. The combination of multiple parameters can improve the differential diagnostic efficacy of SCNs and MCNs (sensitivity = 71.4%, specificity = 77.8%, and AUC = 0.788), and the addition of texture parameters to the conventional parameters allowed a significant reclassification with IDI = 0.236 (95% CI: 0.095-0.377) and categorical NRI = 0.434 (95% CI: 0.030-0.838). SURmax (tumor to normal pancreas ratio, T/P) and SURmax (tumor to aorta ratio, T/A) both showed the highest discriminative diagnostic value (sensitivity = 100.0%, specificity = 70.0%, AUC = 0.900, and Youden index = 0.700) in the differential diagnosis of benign and malignant MCNs, with the cutoff values of 0.84 and 0.90, respectively.

Conclusion

Combination of multiple parameters using ¹⁸F-FDG PET/CT could further improve differentiation between pancreatic SCNs and MCNs. SURmax (T/P) and SURmax (T/A) could improve differential diagnosis of benign and malignant MCNs.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

The Elusive Appearance of Hyperenhancing Solid Serous Cystadenoma of the Pancreas—Radio-Pathological Correlation

Serous cystadenomas account for ~10 to 29% of pancreatic cystic tumors. Solid serous cystadenoma (SSCA) is a rare variant, first described in 1996, with imaging characteristics different from the classical serous cystadenoma of the pancreas and can cause a diagnostic dilemma due to its resemblance to other solid tumors of the pancreas. To the best of our knowledge, only 22 cases of SSCA of pancreas have been reported till date.

A 50-year-old female patient underwent contrast-enhanced computed tomography (CECT) of the abdomen for a hypoechoic lesion detected in the body of the pancreas during ultrasound (US) examination. Due to the hyperenhancement of the well-circumscribed lesion in the arterial phase, a provisional diagnosis of neuroendocrine tumor was considered. Gallium 68-labeled somatostatin-analog (Ga 68-DOTANOC) positron emission tomography CT scan did not show any uptake within the lesion and endoscopic US (EUS)-guided fine-needle aspiration cytology (FNAC) was also inconclusive. She underwent laparotomy and the lesion was enucleated and it was proven to be a serous microcystadenoma on postoperative histopathologic examination.

A diagnosis of SSCA should be considered for solid-appearing pancreatic lesions with characteristic CECT features such as arterial phase hyperenhancement, and immediate washout, along with negative results on DOTANOC scan and EUS-guided FNAC. Malignant transformation of SSCA has not been reported till date, and hence these can be safely followed up, instead of invasive surgery.

Triple threat: pancreatic cystic lesion presenting with spontaneous hemorrhage is found to harbor three distinct neoplasms

Background

Pancreatic serous cystadenoma (SCA) is a benign, cystic lesion with an indolent growth pattern. Complications such as spontaneous hemorrhage or malignant transformation from SCA are extremely rare. Our case report describes an unusual presentation of a patient with a previously diagnosed SCA, made unique by the presence of three separate neoplasms in the final specimen.

Case presentation

A 74-year-old male with a previous diagnosis of SCA presented emergently with epigastric pain and non-bilious vomiting. Laboratory results were notable for a hemoglobin of 8.3 g/dl. CT scan of the abdomen demonstrated a complex, solid-cystic mass in the pancreatic head with a large hematoma and questionable focus of active hemorrhage. Surgical resection was recommended due to the risk of malignancy, possibility of re-bleeding, and symptoms of severe duodenal compression. Pancreaticoduodenectomy was performed, and final pathology demonstrated three separate neoplasms: serous cystadenoma, intraductal papillary mucinous neoplasm, and neuroendocrine tumor.

Conclusion

While pancreatic SCA are benign tumors that can be observed safely in the majority of cases, surgical intervention is often indicated in patients with large, symptomatic cysts or when diagnosis is unclear. When undergoing surveillance, it is crucial for both the patient and the care team to be aware of the possibility of rare, but life-threatening complications, such as hemorrhage. Likewise, the possibility of misdiagnosis or concurrent neoplasia should be considered.

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.

The Value of Contrast-Enhanced Ultrasound Classification in Diagnosis of Pancreatic Cystic Lesions

Objective

To compare the consistency of contrast-enhanced ultrasound (CEUS) classification results with magnetic resonance imaging (MRI) and to investigate the diagnostic value of CEUS classification in pancreatic cystic lesions.

Methods

84 cases of pancreatic cystic lesions were enrolled in this study. According to the CEUS classification methods of previous study in our center, all the lesions were classified into four types: type I, unilocular cysts; type II, microcystic lesions; type III, macrocystic lesions; and type IV, cystic lesions with enhanced solid components. The consistency of CEUS and MRI typing results was analysed. Among the 84 cases, 45 cases had pathological results. The CEUS results were compared with the pathological results, and the diagnostic value of CEUS classification in diagnosing pancreatic cystic lesions was explored.

Results

Among the 84 cases, CEUS diagnosed 8 cases of type I, 24 of type II, 8 of type III, and 45 of type IV. MRI diagnosed 10 cases of type I, 25 of type II, 7 of type III, and 43 of type IV. The classification typing results of CEUS were highly consistent with that of enhanced MRI (kappa value: 0.852). Among the 45 cases with pathological results, the diagnostic accuracy of each type was 91.1%, 95.6%, 93.3%, and 88.9%. The accuracy of CEUS and MRI in diagnosing pancreatic cystic lesions was 75.56% (34/45) and 80% (36/45), respectively. The diagnostic accuracy of CEUS had no significant difference from that of MRI (P=0.687).

Conclusion

The classification results by CEUS and MRI are in excellent agreement. The classification of pancreatic cystic lesions by CEUS is significantly helpful for clinical diagnosis.

Giant serous cystadenoma of the pancreas appearing sonographically as a remote pararenal mass

Macrocystic serous cystadenoma (MSC) of the pancreas is a rare benign neoplasm with varied imaging appearances. We describe an intriguing case of a surgically resected and histologically proven giant MSC, developed in the pararenal space. Ultrasonography (US) revealed a large, oligocystic mass around the lower pole of right kidney. Like US, computed tomography, and magnetic resonance imaging were unable to detect the origin of the lesion, which was only verified at surgical exploration. A bizarre finding was the unusual location of the pancreatic tumor growing seemingly apart from the pancreas itself, with no obvious connection to it.

A case of duodenal hemorrhage due to arteriovenous malformation around a serous cystic neoplasm

Background

No reports have so far described arteriovenous malformation (AVM) in the pancreas caused by a tumor. We herein report a case of pancreatoduodenectomy for a patient who developed duodenal hemorrhage due to AVM developed around serous cystic neoplasm (SCN) of the pancreas.

Case presentation

A 79-year-old man was referred to our hospital because of anemia (Hb 7.4 g/dl) and pancreatic head tumor. Computed tomography showed microcystic-type SCN, 87 mm in size, in the pancreatic head. Vascular hyperplasia had developed around the cystic lesion. Upper gastrointestinal endoscopy and colonoscopy did not reveal the cause of anemia, so the patient was followed closely without hemostatic therapy. Iron preparations had improved the anemia. Three months later, the patient developed anemia (Hb 5.8 g/dl) again. Gastrointestinal endoscopy showed oozing from the mucosa in the duodenum via the swollen vascular hyperplasia. He was diagnosed as duodenal hemorrhage from the blood vessels around SCN. Pancreatoduodenectomy was performed to control repeated duodenal bleeding. A histopathological examination revealed that the cystic lesion in the pancreatic head was SCN, and the AVM developed around SCN and duodenum, causing repeated duodenal hemorrhage. The patient was discharged on postoperative day 22. Nine months after surgery, the patient had no recurrence of anemia.

Conclusions

There have been no reports of duodenal hemorrhage due to acquired pancreatic AVM around pancreatic tumor, including SCN. We successfully treated a case of duodenal hemorrhage due to pancreatic AVM around SCN by pancreatoduodenectomy.

Serous cystadenoma of pancreas: A clinicopathologic experience of 23 cases from a major tertiary care center

Background:

Serous cystadenomas of pancreas are rare benign epithelial neoplasms, which predominantly occur in the pancreatic body and tail of elderly females. Majority of these tumors have microcystic appearance. Macrocystic and solid variants have also been described. A number of more aggressive cystic pancreatic lesions are included in the differential diagnosis. Distinction from such lesions is important for optimal management.

Objective:

Our aim was to study the clinical and histological features of serous cystadenomas which would be helpful in making their correct diagnosis and understanding their behavior.

Methods:

We reviewed 23 cases of serous cystadenomas diagnosed in our institution between January 2001 and June 2018.

Results:

Mean age at presentation was 53.43 years. Female to male ratio was 4.75:1. Over half (56.5%) of the cases were diagnosed incidentally. Abdominal pain was the most common symptom. Body and tail (either alone or in combination) were the most common locations. Tumor size ranged from 2 to 16 cm. Central scar was seen in 43.4% cases. Two cases were unilocular (macrocystic). Microscopically, all cases showed simple cuboidal to flattened epithelium with round, uniform nuclei, and glycogen-rich clear cytoplasm. Focal micropapillae formation was seen in eight cases (34.7%). Surgical resection was performed in 82.6% cases. Recurrence occurred in only one single case.

Conclusion:

Pancreatic serous cystadenomas are benign neoplasms with excellent prognosis. The tumors showed typical morphological features in all cases. Surgical resection was performed in the majority of cases in our study owing to lack of optimal and complete radiological workup pre-operatively and the concern for not missing and adequately treating pancreatic mucinous cystic neoplasms.

The "extracapsular cystic" sign in pancreatic serous cystic neoplasms: A clinicopathologic study of 177 patients with cystic pancreatic lesions

OBJECTIVE

To assess a new imaging feature that we have named the extracapsular cystic sign which can make a constructive contribution towards differentiating serous cystic neoplasms (SCNs) from other pancreatic cystic lesions.

MATERIAL AND METHODS

We retrospectively reviewed 177 CTs/MRIs of patients who underwent pancreatic resection of cystic lesions at two institutions from January 2011/2013, to September 2017. For each patient, demographic information, clinical presentation, especially imaging features were carefully investigated by two experienced abdominal radiologists, retrospectively. All statistical analyses were performed using SPSS V.23.0.

RESULTS

Twenty-one lesions had extracapsular cystic signs which were newly discovered, 17 (28.3%) of 60 SCNs and 4 (3.4%) (mucinous cystic neoplasm = 1, walled-off necrosis = 2, retention cyst = 1) of 117 Non-SCNs were included, from which indicating that the extracapsular cystic sign was more often detected on SCNs. As for 21 lesions, 86% (n = 18) were females, and mean age at diagnosis was 51.2 years. 71% (n = 15) located in the pancreatic body and tail. Average size was 27.2 mm (23.7-53.4), mean (SD) ratio of biggest daughter cyst to mother cyst was 0.51[0.14] (p = 0.99), average (SD) angle between two of them was 105.5° [14.9] (p = 0.84). The average time interval between last imaging examination and surgery was 8.4 days.

CONCLUSIONS

The new sign named the extracapsular cystic sign in SCNs may help differentiate SCNs from other pancreatic cystic lesions. Furthermore, this study supports an original diagnosis for SCNs when the sign of extracapsular cyst appears.

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.

Imaging mimics of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma is the most common primary malignancy of the pancreas. The classic imaging features are a hypovascular mass with proximal ductal dilatation. Different pancreatic pathologies can mimic the imaging appearance of carcinoma including other tumors involving the pancreas (pancreatic neuroendocrine tumors, lymphoma, metastasis, and rare tumors like pancreatic acinar cell carcinoma and solid pseudopapillary tumors), inflammatory processes (chronic pancreatitis and autoimmune pancreatitis), and anatomic variants (annular pancreas). Differentiation between these entities can sometimes be challenging due to overlap of imaging features. The purpose of this article is to describe the common entities that can mimic pancreatic cancer on imaging with illustrative examples and to suggest features that can help in differentiation of these entities.

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.

Solid pseudopapillary neoplasm of the pancreas: CT imaging features and radiologic-pathologic correlation

PURPOSE

We aimed to evaluate the imaging features of solid pseudopapillary neoplasm (SPN) of the pancreas with an emphasis on radiologic-pathologic correlation.

METHODS

Ten patients (all female; mean age, 32 years) with histologic or cytologic diagnosis of SPN encountered between January 2007 and December 2013 were included in this study. Preoperative computed tomography (CT) images were reviewed for location, attenuation, enhancement pattern, margin, shape, size, morphology, presence of capsule and calcification. CT appearances were correlated with histopathologic findings.

RESULTS

Tumors in the distal pancreatic body and tail had a tendency to be larger (mean size 12.6 cm vs. 4.0 cm). Six of the nine tumors that were resected had a fibrous pseudocapsule at histology, five of which could be identified on CT scan. Eight lesions had mixed hypoenhancing solid components and cystic areas corresponding to tumor necrosis and hemorrhage. The two smallest lesions were purely solid and nonencapsulated. Varied patterns of calcification were seen in four tumors. Three of the four pancreatic tail tumors invaded the spleen. At a median follow-up of 53 months, there was no evidence of recurrence in the nine patients who underwent surgical resection of the tumor.

CONCLUSION

A mixed solid and cystic pancreatic mass in a young woman is suggestive of SPN. However, smaller lesions may be completely solid. Splenic invasion can occur in pancreatic tail SPNs; however, in this series it did not adversely affect the long-term outcome.

Serous pancreatic neoplasia, data and review

AIM

To describe the imaging features of serous neoplasms of the pancreas using ultrasound, endoscopic ultrasound, computed tomography and magnetic resonance imaging.

METHODS

This multicenter international collaboration enhances a literature review to date, reporting features of 287 histologically confirmed cases of serous pancreatic cystic neoplasms (SPNs).

RESULTS

Female predominance is seen with most SPNs presenting asymptomatically in the 5^th through 7^th decade. Mean lesion size was 38.7 mm, 98% were single, 44.2% cystic, 46% mixed cystic and solid, and 94% hypoechoic on B-mode ultrasound. Vascular patterns and contrast-enhancement profiles are described as hypervascular and hyperenhancing.

CONCLUSION

The described ultrasound features can aid differentiation of SPN from other neoplastic lesions under most circumstances.

Revisions of international consensus Fukuoka guidelines for the management of IPMN of the pancreas

The management of intraductal papillary mucinous neoplasm (IPMN) continues to evolve. In particular, the indications for resection of branch duct IPMN have changed from early resection to more deliberate observation as proposed by the international consensus guidelines of 2006 and 2012. Another guideline proposed by the American Gastroenterological Association in 2015 restricted indications for surgery more stringently and recommended physicians to stop surveillance if no significant change had occurred in a pancreatic cyst after five years of surveillance, or if a patient underwent resection and a non-malignant IPMN was found. Whether or not it is safe to do so, as well as the method and interval of surveillance, has generated substantial debate. Based on a consensus symposium held during the meeting of the International Association of Pancreatology in Sendai, Japan, in 2016, the working group has revised the guidelines regarding prediction of invasive carcinoma and high-grade dysplasia, surveillance, and postoperative follow-up of IPMN. As the working group did not recognize the need for major revisions of the guidelines, we made only minor revisions and added most recent articles where appropriate. The present guidelines include updated information and recommendations based on our current understanding, and highlight issues that remain controversial or where further research is required.

Serous Microcystic Adenoma of Pancreas: A Case Series from a Tertiary Care Centre in Southern India

Serous microcystic adenoma is a rare exocrine tumour of the cystic neoplasm of pancreas seen predominantly in the elderly population. The first patient was a 56-year-old diabetic woman with abdominal pain, constipation and loss of weight since two months. The second patient was a 73-year-old female with complaints of abdominal pain and back pain since one year. The third patient was a 72-year-old diabetic man with complaints of burning sensation in the right lumbar region since two months. Clinical and laboratory examinations were normal. The radiological examinations of the first two patients showed multiloculated cystic lesion in the pancreas and of the third patient was suggestive of islet cell tumour. The histopathological examination of the three patients showed multiple cysts of varying sizes lined by cuboidal epithelium, showing no atypia. All the three patients were diagnosed as serous microcystic adenoma of pancreas. On follow up, all three patients had no recurrence. Serous epithelial neoplasms need to be differentiated from their non-neoplastic counterparts and other neoplastic lesions with cystic changes, in view of the differences in management. Serous microcystic adenomas have excellent prognosis.

Management of Incidental Pancreatic Cysts: A White Paper of the ACR Incidental Findings Committee

The ACR Incidental Findings Committee (IFC) presents recommendations for managing pancreatic cysts that are incidentally detected on CT or MRI. These recommendations represent an update from the pancreatic component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Pancreas Subcommittee-which included abdominal radiologists, a gastroenterologist, and a pancreatic surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion, and were finalized by informal iterative consensus. Algorithm branches successively categorize pancreatic cysts based on patient characteristics and imaging features. They terminate with an ascertainment of benignity and/or indolence (sufficient to discontinue follow-up), or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected pancreatic cysts.

Longterm follow-up of small pancreatic cystic lesions in liver transplant recipients

Incidental small pancreatic cystic lesions (PCLs) are often found on preoperative imaging in patients undergoing orthotopic liver transplantation (OLT). Although these are considered benign or of low malignant potential, the influence of immunosuppression after OLT may be of concern. The aim of this study was to observe the longterm outcome of these small PCLs in post-OLT patients. An institutional OLT database of 1778 consecutive OLT patients from January 2000 to December 2010 was analyzed. Computed tomography, magnetic resonance imaging, or endoscopic ultrasound at the time of OLT and all subsequent imaging, cytology, fluid analysis of PCLs, and patient status were evaluated. A total of 70 patients with 182 PCLs, of benign or low malignant potential, were identified with a mean follow-up time of 64 months. At initial diagnosis of PCLs in 48 patients, 7 branch duct-type intraductal papillary mucinous neoplasms (B-IPMNs), 1 serous cystadenoma (SCA), and 40 nonspecific benign cysts were identified. Final diagnosis at the end of the follow-up revealed 16 B-IPMNs, 3 SCAs, and a mixed acinar-neuroendocrine carcinoma, in which the latter developed 9 years after initial diagnosis of B-IPMN. During the follow-up time, average increase in size and number of PCLs were 4.5 mm and 1.4, respectively (P < 0.001 for both). The majority of incidental PCLs in OLT patients showed an indolent behavior despite immunosuppression. Risk of malignancy development was very low and comparable with normal population. Liver Transplantation 23 324-329 2017 AASLD.

Enhancing pancreatic mass with normal serum CA19-9: key MDCT features to characterize pancreatic neuroendocrine tumours from its mimics

OBJECTIVES

To determine key MDCT features for characterizing pancreatic neuroendocrine tumours (PNET) from their mimics, which manifest as enhancing pancreatic mass with normal serum CA19-9 level.

METHODS

This retrospective study had institutional review board approval and informed consent was waived. Preoperative multiphase MDCT of 74 patients with enhancing pancreatic masses and normal serum CA19-9 levels were included. Surgical pathologies were PNET (n = 42), microcystic serous cystadenomas (m-SCN, n = 12) and solid pseudopapillary epithelial neoplasms (SPEN, n = 20). Two radiologists independently evaluated CT images with a checklist of findings. Frequencies of findings with each disease entity were compared. Diagnostic accuracy was assessed using the key MDCT features alone and in combination. Inter-observer agreement was evaluated.

RESULTS

The most common findings for PNET were mosaic morphological pattern (33/42, 78.6%) and enhancement peak in pancreatic arterial phase (PAP, 32/42, 76.2%), for m-SCN were honeycomb pattern (9/12, 75.0%) and enhancement peak in PAP (10/12, 83.3%) and for SPEN were melting icecream pattern (16/20, 80.0%) and hypo-enhancement in all phases (18/20, 90.0). Using a combination of morphological patterns and enhancement features, PNET was identified with 88% sensitivity and 81% specificity, m-SCN was identified with 83% sensitivity and 94% specificity, and SPEN was identified with 90% sensitivity and 91% specificity. Inter-observer agreement concerning CT findings was good to excellent (κ = 0.68 to 0.81, all p < 0.01).

CONCLUSIONS

Morphological features and enhancement patterns on MDCT are key features for characterizing enhancing pancreatic mass with normal serum CA19-9. PNET could be differentiated from its mimics with high accuracy.

Giant Serous Cystadenoma of the Pancreas (⩾10 cm): The Clinical Features and CT Findings

Purpose. To report the clinical features and CT manifestations of giant pancreatic serous cystadenoma (≥10 cm). Methods. We retrospectively reviewed the clinical features and CT findings of 6 cases of this entity. Results. All 6 patients were symptomatic. The tumors were 10.2 cm–16.5 cm (median value, 13.0 cm). CT imaging revealed that all 6 cases showed microcystic appearances (n = 5) or mixed microcystic and macrocystic appearances (n = 1). Five patients with tumors at the distal end of the pancreas received distal pancreatectomy. Among these 5 patients, 2 patients underwent partial transverse colon resection or omentum resection due to close adhesion. One patient whose tumor was located in the pancreatic head underwent pancreaticoduodenectomy; however, due to encasement of the portal and superior mesenteric veins, the tumor was incompletely resected. One patient had abundant draining veins on the tumor surface and suffered large blood loss (700 mL). After 6–49 months of follow-up the 6 patients showed no tumor recurrence or signs of malignant transformation. Conclusions. Giant pancreatic serous cystadenoma necessitates surgical resection due to large size, symptoms, uncertain diagnosis, and adjacent organ compression. The relationship between the tumors and the neighboring organs needs to be carefully assessed before operation on CT image.

AACE/ACE disease state clinical review: pancreatic neuroendocrine incidentalomas

Incidental detection of pancreatic neuroendocrine tumors (PNETs) has substantially increased over the last decade due to widespread use of advanced imaging studies. Reliable initial imaging-based characterization is crucial for the differential diagnosis from other exocrine neoplasms and to determine the appropriate management plan. Measurements of chromogranin A, pancreatic polypeptide, and calcitonin are recommended for the biochemical evaluation. A thorough medical history needs to be performed to rule out multiple endocrine neoplasia (MEN) type 1. The European Neuroendocrine Tumor Society (ENETS)/Tumor Node Metastasis (TNM) staging system together with a grading based on the Ki-67 proliferation index and mitotic counts has proven to give more appropriate prognostic information than the World Health Organization (WHO)/American Joint Committee on Cancer (AJCC) TNM staging but may still fail to safely differentiate benign from malignant lesions. Poorly differentiated PNETs generally present with metastases and are rarely amenable for resection. Well- or intermediately differentiated tumors ≥2 cm with imaging evidence of malignancy or with a Ki-67 >2% should be resected. It has been suggested that non-MEN related, nonfunctioning, and asymptomatic PNETs <2 cm with a Ki-67 index ≤2% carry a low risk of metastasis and may be observed in the absence of clinical or radiologic criteria of malignancy or progression, especially in older patients. However, because metastases may occur with long delay with smaller PNETS, physicians should consider patient age, lesion location, and the risks of operation, and patients not undergoing surgery need to be closely followed closely.

Current perspectives on pancreatic serous cystic neoplasms: Diagnosis, management and beyond

Pancreatic cystic neoplasms have been increasingly recognized recently. Comprising about 16% of all resected pancreatic cystic neoplasms, serous cystic neoplasms are uncommon benign lesions that are usually asymptomatic and found incidentally. Despite overall low risk of malignancy, these pancreatic cysts still generate anxiety, leading to intensive medical investigations with considerable financial cost to health care systems. This review discusses the general background of serous cystic neoplasms, including epidemiology and clinical characteristics, and provides an updated overview of diagnostic approaches based on clinical features, relevant imaging studies and new findings that are being discovered pertaining to diagnostic evaluation. We also concisely discuss and propose management strategies for better quality of life.

Serous cystadenoma of the pancreas with atypical clinical manifestations: A case report

The present study reported a 4.8 cm space-occupying cystic solid mass of the pancreas, which caused recurrent bilateral lower back discomfort in a 60-year-old female. Combined with the clinical data, an impression of a solid-pseudopapillary neoplasm was generated prior to surgery. Abdominal exploration revealed splenic vessel encasement by the mass similar to the invasion observed in a malignant tumor. Distal pancreatectomy with splenectomy was subsequently performed. Grossly, the tumor was solid and consisted of numerous small cysts. Histopathological examination of the cystic solid mass revealed classic microcystic serous cystadenoma of the pancreas. These findings suggested that microcystic serous cystadenoma can exhibit atypical clinical manifestations. Asymptomatic patients with a small lesion (<4 cm) require imaging surveillance every 2 years; however, tumors >4 cm with atypical presentations require surgical resection.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

OBJECTIVES

Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality.

DESIGN

Retrospective multinational study including SCN diagnosed between 1990 and 2014.

RESULTS

2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1).

CONCLUSIONS

After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN.

TRIAL REGISTRATION NUMBER

IRB 00006477.

Macrocystic serous cystadenoma of the pancreas: Report of 4 cases

BACKGROUND

Macrocystic serous cystadenomas (MaSCA) are rare benign tumor of the pancreas which represent an atypical macroscopic morphologic variant of serous cystadenomas (SCA). They are characterized by a limited number of cysts with a diameter of >2 cm and share imaging features overlapping those of mucinous cystic neoplasm (MCN) and branch-duct intraductal papillary mucinous neoplasm (BD-IPMN), thus frequently making the pre-operative radiologic diagnosis difficult.

MATERIALS AND METHODS

Four cases of MaSCA, which were surgically treated in our structure, are reported.

RESULTS

Two women (62 and 39 year-old) presented with upper abdominal pain and palpable mass underwent CT with evidence of a lobulated cystic neoformation (98 × 70 and 94 × 75 mm respectively) originating from the body and the tail of the pancreas respectively. They underwent distal pancreatectomy for suspected MCN. A 38 year-old woman underwent laparoscopic distal pancreatectomy because of the incidental finding of an unilocular cystic lesion in the pancreatic tail (23 mm) of indeterminate origin (MCN, SCA or metastasis). In a 40 year-old woman, admitted for acalculous acute pancreatitis, an unilocular cystic lesion in the body of the pancreas (62 mm) was detected and confirmed after 2 months at CT, therefore she underwent distal pancreatectomy for suspected pseudocyst or SCA. In all of the 4 patients the histological examination of the specimens revealed a MaSCA.

CONCLUSION

Imaging techniques have a low diagnostic power in terms of differentiation of MaSCA from malignant lesions (as MCNs and BD-IPMN). In the clinical practise of MaSCA, surgery appears to gain indications that are wider than those correlated to the pathologic outcome, because of the necessity of a correct differential diagnosis from potentially malignant cystic tumors and the frequent symptoms requiring treatment.

Management of serous cystic neoplasms of the pancreas

Pancreatic serous cystadenomas are uncommon benign tumours that are often found incidentally on routine imaging examinations. Radiological imaging techniques alone have proven to be suboptimal to fully characterize cystic pancreatic lesions. Endoscopic ultrasound, with the addition of fine-needle aspiration in difficult cases, has showed greater diagnostic accuracy than conventional imaging techniques. The best management strategy of these neoplasms is still debated. Surgery should be limited only to symptomatic and highly selected cases and most of the patients should only be strictly monitored. In the current paper, we provide an updated overview on pancreatic serous cystadenomas, focusing our attention on epidemiology, clinical characteristics and diagnostic evaluation; finally, we also discuss different management strategies and areas for future research.