While serous cystadenomas of the pancreas usually consist of small cysts, one rare variant has been reported to be composed of macrocysts. Herein, we present the case of the youngest patient with macrocystic serous cystadenoma (MSC) to be reported in the literature. The patient was a 17-year-old girl who presented with the major symptoms of a palpable abdominal mass accompanied by epigastric pain and vomiting for several months. A potential malignancy could not be excluded on the basis of imaging studies, which showed a large macrocystic pancreatic tumor that was 7 cm in diameter. Owing to the patient's symptoms, after diagnosing the mass as a pancreatic cystic tumor with potential malignancy and large tumor size, surgical intervention was arranged. Pathological analysis of the biopsy sample suggested MSC. By reviewing the literature, we found several unique characters of MSCs that cause them to be frequently misdiagnosed as potential malignancies. Additionally, the age of MSC occurrence was found to be lower than of general serous cystadenomas. The potential of MSC should be kept in mind by clinicians when diagnosing young people with pancreatic macrocystic lesions.

Background and Aim: The frequency of detection of pancreatic cystic lesions (PCLs) in magnetic resonance imaging performed for reasons unrelated to the pancreas reaches up to 13.5%. The aim of this study was to evaluate the role of cyst fluid interleukin 1 beta (IL1β) and different endoscopic ultrasound (EUS) features in differentiating premalignant/malignant from benign pancreatic cysts. In addition, to evaluate the role of pancreatic cyst fluid carcinoembryonic antigen (CEA) in differentiating mucinous from nonmucinous pancreatic cysts. Methods: This study was conducted on 73 patients with PCLs. EUS-guided fine-needle aspiration (EUS-FNA) was performed on all patients. Estimation of IL1β and CEA levels in aspirated specimens were carried out. Results: Pancreatic cyst fluid IL1β level could not differentiate between premalignant/malignant and benign pancreatic cysts. At a cutoff value of 19.81 ng/mL pancreatic cyst fluid CEA has 64.3% sensitivity and 84.4% specificity in differentiating mucinous from nonmucinous pancreatic cyst. EUS can differentiate between premalignant/malignant pancreatic cysts and benign cysts with a sensitivity of 66.7%, specificity of 69.2% Conclusions: Pancreatic cyst fluid IL1β level cannot differentiate between premalignant/malignant and benign pancreatic cysts. CEA level can help in differentiation between mucinous and nonmucinous cysts. EUS can be useful in differentiation between premalignant/malignant pancreatic cysts and benign cysts.

Cystic pancreatic lesions involve a wide variety of pathological entities that include neoplastic and non-neoplastic lesions. The proper diagnosis, differentiation, and staging of these cystic lesions are considered a crucial issue in planning further management. There are great challenges for their diagnostic models. In our time, new emerging methods for this diagnosis have been discovered. Endoscopic ultrasonography-guided fine-needle aspiration cytology with chemical and molecular analysis of cyst fluid and EUS-guided fine needle-based confocal laser endomicroscopy, through the needle microforceps biopsy, and single-operator cholangioscopy/pancreatoscopy are promising methods that have been used in the diagnosis of cystic pancreatic lesions. Hereby we discuss the diagnosis of cystic pancreatic lesions and the benefits of various diagnostic models.

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).

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.

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%).

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.

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.

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.

Cystic pancreatic lesions vary from benign to malignant entities and are increasingly detected on cross-sectional imaging. Knowledge of the imaging appearances of cystic pancreatic lesions may help radiologists in their diagnostic reporting and management. In this review, we discuss the morphologic classification of these lesions based on a diagnostic algorithm as well as the management of these lesions.

Little is known about whether the 2006 Sendai guidelines or 2012 Fukuoka guidelines are being used to determine the level of risk posed by suspected pancreatic mucinous cystic neoplasms (PCNs). We evaluated whether the guidelines accurately predicted which patients with suspected PCNs, which was based on cross-sectional imaging findings, would be found to have advanced neoplasia in surgery.

We performed a retrospective study of data collected from 194 patients with cystic lesions of the pancreas, which were assessed by cross-sectional imaging analyses, who underwent surgery for suspected PCNs at the Hospital at the University of Pennsylvania from 2000 through 2008. Imaging data were used to classify patients according to the Sendai guidelines as high risk or low risk and according to the Fukuoka guidelines as high risk, worrisome, or low risk. Pathology analyses of samples collected during surgery were used as the reference. A logistic regression model was created to identify factors associated with advanced neoplasia. The Sendai and Fukuoka guideline criteria were analyzed by univariate and multivariable logistic regression analyses.

Advanced neoplasias were found in 36 patients (18.5%; 22 invasive cancers and 14 high-grade dysplasias). The median size of cysts was 33 mm. All patients found to have invasive cancers were accurately assigned to the Sendai guidelines high risk or Fukuoka guidelines high risk groups. However, 3 patients in the Sendai guidelines low risk and 2 patients in the Fukuoka guidelines low risk groups were found to have high-grade dysplasia. The Sendai guidelines identified patients with advanced neoplasia with 91.7% sensitivity, 21.5% specificity, 21% positive predictive value, and 91.9% negative predictive value. A designation of Fukuoka guidelines high risk identified patients with advanced neoplasia with 55.6% sensitivity, 73% specificity, 32% positive predictive value, and 87.9% negative predictive value. Overall, there was no statistically significant difference between the guidelines in predicting which patients had advanced neoplasia. On multivariate analysis, the presence of a mural nodule (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.33-6.27; P = .008), dilated main pancreatic duct >10 mm (OR, 7.44; 95% CI, 2.36-23.52; P = .001), or enhancing solid component (OR, 2.92; 95% CI, 1.16-7.64; P = .02) were associated with detection of advanced neoplasia in pancreatic cysts.

On the basis of a retrospective analysis, the Sendai and Fukuoka guidelines accurately determine which patients with pancreatic cysts have advanced neoplasia. The guidelines accurately recommended surgical resection for all patients found to have invasive cancer, although some patients with high-grade dysplasia were missed. The updated Fukuoka guidelines are not superior to the Sendai guidelines in identifying neoplasias. Cyst size was not associated with advanced neoplasia.

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.

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

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.

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.

We herein summarize the pathology and most recent advances in the molecular genetics of serous cystic neoplasms of the pancreas. They typically present as relatively large, well-demarcated tumors (mean size, 6cm), predominantly occurring in females. Pre-operative diagnosis remains challenging; imaging findings and cyst fluid analysis often prove non-specific and fine-needle aspiration often does not yield diagnostic cells. Pathologically, they are characterized by a distinctive cytology referred to as "serous." Although they have ductal differentiation, they distinctly lack the mucin production that characterizes most other pancreatic ductal tumors, including ductal adenocarcinoma and its variants, intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). They instead produce abundant glycogen (glycogen-rich adenoma). Serous cystadenomas also lack the molecular alterations that characterize ductal neoplasms, such as mutation of KRAS (high prevalence in most mucinous ductal neoplasms), inactivation of SMAD4 (seen in ductal adenocarcinomas), and mutations in GNAS (seen in some IPMNs) and RNF43 (detected in MCNs and IPMNs). Instead, new molecular and immunohistochemical observations place serous pancreatic tumors closer to "clear cell neoplasms" seen in various other organs that are associated with the von Hippel-Lindau (VHL) pathway, such as clear cell renal cell carcinomas and capillary hemangioblastomas. Patients with VHL syndrome have an increased risk of developing serous pancreatic tumors and somatic mutations of the VHL gene are common in these tumors along with modification of its downstream effectors including hypoxia-inducible factor (HIF1), glucose uptake and transporter-1 (GLUT-1), a common factor in clear cell (glycogen-rich) tumors, as well as expression of vascular endothelial growth factor (VEGF), thought to be a factor in the striking capillarization of serous cystadenomas and other non-pancreatic clear cell tumors. VEGF may prove to be of significant diagnostic value since its elevation in cyst fluid has recently been found highly sensitive and specific for serous neoplasms. These molecular alterations establish serous tumors as prototypes of clear cell tumorigenesis and angiogenesis and may prove helpful both as diagnostic and non-surgical therapeutic targets.

To investigate the imaging characteristics of pancreatic serous oligocystic adenoma (SOA) and mucinous cystic neoplasms (MCNs) using spectral computed tomography (CT) and to evaluate whether quantitative information derived from spectral imaging can improve the differential diagnosis of these diseases.

From February 2010 to June 2013, 44 patients (24 SOAs and 20 MCNs) who underwent spectral CT imaging were included in the study. Conventional characteristics and quantitative parameters were compared between the two disease groups. Logistic regression was used for multiparametric analysis. The receiver-operating characteristic curve was used to evaluate the diagnostic performance of single parameter and multiparametric analysis. Two radiologists diagnosed the diseases blinded and independently, without and with the information of the statistical analysis.

Tumour location, contour, size, and monochromatic CT values at 40 keV to 70 keV, iodine concentration, and effective atomic number (effective-Z) in the late arterial phase were the independent factors correlated with category. Multiparametric analysis with logistic regression showed that tumour size, location, and contour were the most effective variations, and obtained an area under the ROC curve (AUC) of 0.934. With the knowledge of statistical analysis, the accuracy of the first reader increased from 70.5% to 86.4%, and the accuracy of the second reader increased from 81.8% to 90.9%.

Although CT spectral imaging provided additional information and multiparametric analysis obtained better performance than single-parameter analysis in differentiating MCNs from SOAs, multiparametric analysis with the combination of quantitative parameters derived from CT spectral imaging did not improve the diagnostic performance. Tumour size, location, and contour played an important role in differentiating MCNs from SOAs.

Cystic lesions of the pancreas are relatively common findings at cross-sectional imaging; however, classification of these lesions on the basis of imaging features alone can sometimes be difficult. Complementary evaluation with endoscopic ultrasonography and fine-needle aspiration may be helpful in the diagnosis of these lesions. Cystic lesions of the pancreas may range from benign to malignant and include both primary cystic lesions of the pancreas (including intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystadenomas, pseudocysts, and true epithelial cysts) and solid neoplasms undergoing cystic degeneration (including neuroendocrine tumors, solid pseudopapillary neoplasms, and, rarely, adenocarcinoma and its variants). Familiarity with the imaging features of these lesions and the basic treatment algorithms is essential for radiologists, as collaboration with gastroenterologists and surgeons is often necessary to obtain an early and accurate diagnosis.

Pancreatic serous cystadenomas are benign cystic neoplasms. Extensive degeneration mimicking a pancreatic pseudocyst has been described in several types of pancreatic neoplasms but has not been documented in serous cystadenomas. We report subtotal cystic degeneration of microcystic serous cystadenomas (MSCA) that produces radiographic, gross, and microscopic overlap with pancreatic pseudocyst.

Resected MSCA with degenerative change were identified from the pathology archives of Memorial Sloan-Kettering Cancer Center and Johns Hopkins Hospital. The clinical, radiographic, gross, and microscopic findings were reviewed.

Eight MSCAs with subtotal cystic degeneration were retrieved from among 397 resected serous cystadenomas (2.0%). There were 2 men and 6 women (mean age, 52 y). Available radiographic studies showed classic features of MSCA in 2 of 4 cases. Four cysts were unilocular, and 4 were multilocular. Gross features of MSCA were noted focally in the multilocular cases but were not evident in the unilocular examples. The predominant histologic features were those of pancreatic pseudocyst, including a fibrotic cyst wall lacking epithelium and instead composed of myofibroblastic proliferation, hemorrhage, and inflammation. Residual foci of MSCA were embedded in fibrosis, comprising 5% to 60% of the tumor volume.

Most pancreatic serous cystadenomas display characteristic morphology, including a glycogen-rich epithelial lining and prominent subepithelial capillaries; however, extensive degenerative macrocystic change can obscure these classic features. This phenomenon is to be distinguished from macrocystic serous cystadenoma, in which thin-walled macrocystic spaces are epithelium lined. Thus, serous cystadenoma should be included in the differential diagnosis of pancreatic masses with extensive degenerative cystic change.

Although little is known on the true prevalence of pancreatic cysts, physicians are currently more frequently confronted with pancreatic cysts because of the increasing use of sophisticated cross-sectional abdominal imaging. Cystic lesions of the pancreas comprise of a heterogeneous group of diagnostic entities, some of which are benign such as inflammatory pseudocysts or serous cystadenomas and do not require resection when asymptomatic. Others like mucinous cysts or intraductal papillary mucinous neoplasms (IPMN) have a malignant potential and in these cases surgical resection is often indicated. For this reason an adequate distinction between the various cysts is crucial to optimize management strategy. Different diagnostic methods that could be of value in the differentiation include radiologic imaging techniques such as CT, MR, and endosonography. In addition, fluid aspiration for cytopathology, tumormarkers or molecular analysis is widely used. Different guidelines are available but so far no optimal diagnostic algorithm exists. We summarize the epidemiology, classification, clinical presentation, diagnostics, management, and future perspectives.

The purpose of this study was to describe the MRI features of the benign pancreatic neoplasm serous oligocystic adenoma (SOA) that differ from those of mucinous cystic neoplasm (MCN), a neoplasm with the potential for malignant degeneration.

Seven patients with SOA (seven women; mean age 36.6 years) and eight patients with MCN (eight women: mean age 39.9 years) were included. Several imaging features were reviewed: mass size, location, shape, wall thickness, cyst configuration (Type I, unilocular; Type II, multiple clustered cyst; Type III, cyst with internal septation) and signal intensity of the lesion with heterogeneity.

SOA lesions were smaller (3.4 cm) than those of MCN (9.3 cm) (p=0.023). The commonest lesion shape was lobulated (85.7%) for SOA, but oval (50.0%) or lobulated (37.5%) for MCN (p=0.015). The most common cyst configuration was Type II (85.7%) for SOA and Type III (75.0%) for MCN (p=0.008). Heterogeneity of each locule in T(1) weighted images was visible in all cases of MCN, but in no case for SOA (p=0.004).

SOA could be differentiated from MCN by identifying the imaging features of lobulated contour with multiple clustered cyst configurations and homogeneity of each locule in T(1) weighted MR images.

The aim of this study is to retrospectively analyze the variety of CT findings based on new pathologic classification.

During a 10-year period, 59 histopathologically proven pancreatic SCTs and 13 SCTs confirmed with typical image findings and strict clinical criteria were enlisted. Two radiologists analyzed CT images for the following items in consensus: location, size, outer margin, tumor shape, the presence of mural nodule, communication with main pancreatic duct (MPD), the presence and extent of MPD dilatation, calcification, central scar, and attenuation on pre- and post-contrast CT images. In addition, typicality of CT findings was determined. A typical finding was defined as a honeycomb appearance without or with oligocystic portion. In the cases with atypical features, the type of atypical features and differential diagnosis were recorded. For the shape of the tumor, tumors were categorized into the following groups: honeycomb without or with oligocystic, pleomorphic, purely oligolocular, unilocular cystic, hypovascular solid, hypervascular solid without or with oligocystic portion, and fingerlike cystic patterns.

28 SCTs (38.9%) presented a honeycomb appearance with (n=14) or without oligocystic portion (n=14) and were classified as typical cases. The remaining 44 atypical cases (61.1%) presented the following: purely oligolocular pattern in 18; hypervascular solid without (n=7) or with oligocystic portion (n=2) in 9; pleomorphic in 8; unilocular cystic in 7; and fingerlike cystic pattern in 2. Most of the lesions manifesting as hypervascular solid lesions were confused with true solid hypervascular tumors such as neuroendocrine tumors or solid pseudopapillary tumors. For most of the remaining atypical lesions, mucinous cystic neoplasm or branch duct type IPMN were included as a differential diagnosis.

Serous cystic tumors of the pancreas can have variable CT appearances ranging from compactly solid hypervascular to clearly unilocular cystic, which reflect a varied macroscopic morphology. Only 38.9% of the SCTs show traditional typical CT features whereas a considerable proportion (61.1%) of SCTs showed atypical appearances, providing diagnostic challenges to radiologists.

The diagnosis of serous microcystic adenoma (SMA) is usually straightforward. For small biopsies and/or unusual variants, the differential diagnosis includes other pancreatic or metastatic neoplasms showing cystic or clear cell features. We evaluated immunostains for potential use in the diagnosis of SMA. Cases of SMA were identified from archival files. Tissue cores (2 per block) were arrayed to create a microarray of cores measuring 2mm each. Additionally, microarrays previously constructed from 56 pancreatic adenocarcinomas (PACs) and 64 pancreatic endocrine tumors (PENs) were studied. The microarrays were stained with calponin, chromogranin, CD10, alpha-inhibin, and monoclonal neuron-specific enolase (m-NSE). Subsequently, some were stained with MUC6, melan-A, D2-40, h-caldesmon, smooth muscle actin, and smooth muscle myosin. For SMAs, staining was seen with calponin (85.2%), alpha-inhibin (96.2%), and m-NSE (96.2%). Focal weak staining was seen with MUC6 (65%). All SMAs were negative with chromogranin, CD10, melan-A, D2-40, h-caldesmon, smooth muscle actin, and smooth muscle myosin. In contrast, calponin was negative in all PACs and PENs. Staining for alpha-inhibin was absent in PACs and present in 4.1% of PENs; whereas immunoreactivity for m-NSE was present in 26.8% of PACs and 73.7% of PENs. Chromogranin staining was present in 9.1% of PACs and 100% of PENs. An immunohistochemical profile of staining with calponin, alpha-inhibin, and m-NSE and absent staining with chromogranin supports the diagnosis of SMA, and distinguishes SMA from PAC and PEN. Calponin and alpha-inhibin are the most useful positive markers for SMA, and are negative in most entities in the differential diagnosis.

Pancreatic cytopathology plays an important role in the diagnosis and management of patients with solid and cystic lesions of the pancreas.

To serve as a practical guide to pancreatic cytopathology for the practicing pathologist. Data Sources.-A comprehensive assessment of the medical literature was performed.

We review pancreatic cytopathology, with specific discussions of its role in patient management, specimen types and specimen processing, specific diagnostic criteria, and the use of ancillary testing and advanced techniques.

Cystic lesions of the pancreas are being recognized with increasing frequency and have become a more common finding in clinical practice because of the widespread use of advanced imaging modalities and the sharp drop in the mortality rate of pancreatic surgery. Consequently, in the past 2 decades, the nature of many cystic tumors in this organ has been better characterized, and significant developments have taken place in the classification and in our understanding of pancreatic cystic lesions.

To provide an overview of the current concepts in classification, differential diagnosis, and clinical/biologic behavior of pancreatic cystic tumors.

The authors' personal experience, based on institutional and consultation materials, combined with an analysis of the literature.

In contrast to solid tumors, most of which are invasive ductal adenocarcinomas with dismal prognosis, cystic lesions of the pancreas are often either benign or low-grade indolent neoplasia. However, those that are mucinous, namely, intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, constitute an important category because they have well-established malignant potential, representing an adenoma-carcinoma sequence. Those that are nonmucinous such as serous tumors, congenital cysts, lymphoepithelial cysts, and squamoid cyst of pancreatic ducts have no malignant potential. Only rare nonmucinous cystic tumors that occur as a result of degenerative/necrotic changes in otherwise solid neoplasia, such as cystic ductal adenocarcinomas, cystic pancreatic endocrine neoplasia, and solid-pseudopapillary neoplasm, are also malignant and have variable degrees of aggressiveness.

Serous oligocystic adenoma (SOA), a rare pancreatic neoplasm, is generally a benign lesion without the necessity of surgery. Preoperatively, it is difficult to discriminate SOA from mucinous cystic neoplasm (MCN), which essentially needs surgical treatment. The purpose of this study was to evaluate the cyst wall thickness of SOAs and MCNs for preoperative differential diagnosis.

We experienced three cases of SOAs with typical histopathological features. The cyst wall thickness of the SOAs was evaluated in the area protruding out of the pancreas and was compared with that of 13 MCNs histopathologically. The same evaluation and comparison were conducted on preoperative computed tomography (CT) images retrospectively.

The SOAs had a uniformly thin cyst wall measuring less than 1 mm. In contrast, the largest area of a cyst wall in MCNs ranged from 2.5 to 10.0 mm. On CT images, all but one of the MCNs showed a detectable cyst wall, while the cyst walls were hardly recognizable in two of the three SOAs.

For preoperative differentiation between SOAs and MCNs, the evaluation of cyst wall thickness may be an important tool and may contribute to the decision of treatment strategy.

This article describes the appearance of miscellaneous cystic and endocrine neoplasms using magnetic resonance imaging (MRI). Magnetic resonance imaging is a useful diagnostic modality in the assessment of various pancreatic neoplasms. Pancreatic endocrine tumors are moderately low in signal intensity on T1-weighted fat-suppressed images and moderately high in signal intensity on T2-weighted fat-suppressed images and demonstrate homogeneous, ring, or diffuse heterogeneous enhancement on immediate postgadolinium gradient echo images. Cystic pancreatic neoplasms, including intraductal papillary mucinous neoplasm, are well demonstrated and subcategorized according to their characteristic cystic configurations on MRI and MR cholangiopancreatography images. Microcystic serous cystadenomas are demonstrated as a honeycombed appearance on T2-weighted images and have a central stellate scar. Mucinous cystic neoplasms usually appear as multilocular cystic masses, with benign forms of macrocystic tumors possessing uniform thickness septations and malignant forms exhibiting irregular septations and tumor nodules. The presence of tumor stroma, invasion of adjacent tissue, or liver metastases can be assessed by MRI. The connection between the pancreatic duct and the cystic tumor is usually well shown on MR cholangiopancreatography images.

Pancreatic cystic lesions are being detected more frequently given increased use of cross-sectional imaging modalities. The most common cysts encountered are mucinous cysts, which have malignant potential. As many of these lesions are incidental findings, it is important to further evaluate them with endoscopic ultrasound-guided fine needle aspiration for diagnostic purposes and risk stratification. These cysts either require surgical resection or surveillance given the malignant risk. Mucinous cystic neoplasms should be resected. Intraductal papillary mucinous neoplasia (IPMN) has consensus-guideline indications for resection. These include main duct diameter > or = 10 mm, a branch duct size > or = 3 cm, presence of a mural nodule, or cytology suspicious for malignancy. Additionally, all symptomatic cysts, regardless of etiology, should undergo resection. Branch duct IPMN is less aggressive that the main duct variety, and may be conservatively followed. However, the development of an established indication for resection should prompt surgery. Despite generalized guidelines, decisions regarding management of pancreatic cysts should be individualized, accounting for the malignant risk of the lesion and the surgical risk of the patient.

Serous microcystic adenoma is a rare benign tumor of the exocrine pancreas originating from the ductal system and composed of a large number of small cysts covered by cuboid cells, filled with clear serous fluid and separated with fibrocolagenous stroma. Most frequently it appears in women in 7th and 8th decades, in the distal pancreas. It shows a very low malignant potential. In 2/3 of patients symptoms are uncharacteristic and in 1/3 they are absent When localised within the head of the pancreas it rarely causes an obstructive jaundice.

We presented a 61-year-old female patient who for months had had mild and nonspecific abdominal symptoms developing to progressive obstructive jaundice. At surgery we revealed a rather large policystic mass of the head of the pancreas causing not only obstructive jaundice but also a venous stasis by compression and dislocation of the portomesenteric vein. The tumor was removed with pylorus preserving cephalic duodenopancreatectomy (Whipple's procedure modified by Longmire-Traverso). Histology confirmed serous microcystic adenoma of the pancreas. The postoperative recovery was uneventful and preoperative symptoms disappeared.

Although very rare, serous microcystic adenoma might appear within the head of the pancreas and has to be taken into consideration in differential diagnosis of cystic lesions of the head of the pancreas. Very rarely the tumour might cause obstructive jaundice. Surgical resection, which might be demanding, leads to complete recovery.

To determine the frequency of typical features of pancreatic cystic lesions on high-resolution computed tomography and the combination of features that best influences discrimination.

Ten computed tomography features of 100 proven pancreatic cystic lesions were retrospectively tabulated by 2 blinded imagers. After final diagnosis was revealed, each lesion was categorized as typical or atypical. Stepwise multivariable logistic regression was used to determine which of 10 imaging and 4 clinical features significantly distinguished between benign and malignant lesions.

There were 38 benign cysts and 62 cystic tumors. Serous lesions presented with greater than 6 cysts (83%) and cysts of less than 2 cm (44%). Mucinous lesions presented with cysts of 2 cm or greater (82%) and less than 6 cysts (64%). Pseudocysts, serous, and mucinous lesions presented typically in 77%, 67%, and 64% of cases, respectively. The significant variables in classifying malignant lesions are pancreatitis history, cyst size, symptoms, and calcification pattern (area under the curve, 0.837).

Four specific imaging and clinical features in combination best predict a malignant lesion.

To report the clinicopathological features of patients with serous cystadenomas of the pancreas.

Thirty-three cases of serous cystadenoma diagnosed between 1977 and 2006 were retrieved from the files of the Ohio State University Medical Center. Clinical data and microscopic slides were reviewed.

The patients included 27 women and 6 men with an age range of 38-83 (mean 64.3) years. The clinical presentation included 13 patients with abdominal pain and 8 patients with abdominal mass; 9 tumors were found incidentally. Abdominal CT scans in 25 patients were interpreted as suspicious for carcinoma in 8 (32%), suspicious for serous cystadenoma in 8, neoplasm not otherwise specified in 8, and suspicious for a pseudocyst in 1. Only 7 patients underwent a preoperative biopsy, and 5 of these were diagnosed as having a serous cystadenoma. All but 2 of the patients underwent surgical resection of the tumor. The serous cystadenomas varied in size from 1.0 to up to 13 cm in maximum dimension, and all but one had a multicystic appearance. Of the 33 serous cystadenomas, 20 (61%) were located in the pancreatic tail, 4 (12%) in the pancreatic body, 4 in the pancreatic body and tail, and 5 (15%) in the head of the pancreas. Follow-up in 17 patients (median 3 years, range from 1 month to 11 years) showed no recurrence of serous cystadenomas. One patient had von Hippel-Lindau syndrome, 4 patients had diabetes mellitus, 3 patients had metastatic cancer, and 2 patients had ovarian tumors.

Serous cystadenoma is an uncommon neoplasm that can be confused with malignancy both clinically and radiologically; a correct diagnosis is important in order to provide an accurate prognosis.

Serous cystadenoma of the pancreas is a diagnosis being entertained with increasing frequency. The histopathologic findings, diagnostic strategy, differential diagnosis, and treatment strategy of these generally benign but sometimes symptomatic lesions are discussed. Based on the available case series, surgical resection should be considered in good-risk patients with symptomatic tumors, with tumors at least 4 cm in maximum diameter, or in whom a more worrisome diagnosis cannot be excluded.

Serous oligocystic or macrocystic adenoma of the pancreas is a very uncommon morphological variant of what was classically termed microcystic adenoma of the pancreas. This is a benign neoplasm; however, its radiological appearance mimicks that of potentially malignant mucinous neoplasms of the pancreas. Therefore, radiologists need to be familiar with this entity to ensure the most appropriate therapeutic management and help to avoid unnecessary surgery.

The diagnosis and management of pancreatic cystic lesions is a common problem. At least 1% of hospitalized patients at major medical centers will have a pancreatic cystic lesion on cross sectional imaging. Up to a quarter of all pancreata examined in an autopsy series contained a pancreatic cyst, 16% of which were lined by an "atypical" epithelium and 3% of which had progressed to carcinoma-in-situ (high grade dysplasia). in the past, it was thought these cystic lesions were benign, but increasing evidence points to the cystic lesions as being the origin of some pancreatic malignancies. The most important clinical tools in the diagnosis and management of pancreatic cystic lesions are cross sectional imaging, endoscopic ultrasound, and cyst fluid analysis. The most important differential diagnosis is distinguishing mucinous (pre-malignant) and non-mucinous cystic lesions. The findings of a macrocystic lesion containing viscous fluid rich in CEA are supportive of a diagnosis of a mucinous lesion. Serous lesion are the most common non-mucinous cyst and are characterized by a microcystic morphology, non-viscous fluid and a low concentration of CEA in the cyst fluid. The following document includes a description of neoplastic pancreatic cysts, a critical review of relevant diagnostic tests, and a discussion of treatment options. We have proposed a set of guidelines for the diagnosis and management of patients with neoplastic pancreatic cysts. The guidelines are based on published data backed by an analysis of the quality of the data and are designed to address the most frequent and important clinical scenarios. In addition to providing a summary of the diagnostic data, we offer diagnostic and management suggestions based on 13 common clinical problems. Although the field is rapidly evolving, a set of core principles is provided based on a balance between the risk of malignancy and the benefit of pancreatic resection.

The increasing use of radiological imaging has led to greater detection of small and asymptomatic cystic lesions of the pancreas. Most are resectable, but not all are neoplastic. This review provides an update on the histopathology, immunohistochemistry, molecular biology, pathogenesis and management of cystic neoplasms of the exocrine pancreas. These include the serous, the mucinous cystic, the intraductal papillary mucinous and the solid pseudopapillary neoplasms. Recently reported variants are described and very rare cystic variants of other pancreatic epithelial and mesenchymal neoplasms are briefly mentioned.

This article presents the approach to the most commonly encountered pancreatic cystic masses that the authors employ at the University of Pittsburgh Medical Center. Variations on this approach are to be expected, based on several factors, including the availability of sophisticated imaging equipment and personnel.

Although cystic tumors of the pancreas are relatively rare, they constitute an increasingly important category. Advances in imaging and interventional techniques and the sharp drop in the mortality rate of pancreatic surgery have rendered pancreatic biopsies and resections commonplace specimens. Consequently, in the past two decades, the nature of many cystic tumors in this organ has been better characterized. The names of some existing entities were revised; for example, what was known as papillary-cystic tumor is now regarded as solid-pseudopapillary tumor. New entities, in particular, intraductal papillary mucinous neoplasm and its variants, such as oncocytic and intestinal subtypes were recognized. The importance of clinical and pathologic correlation in the evaluation of these lesions was appreciated, in particular, with regards to the multifocality of these lesions, their association with invasive carcinomas, and thus their 'preinvasive' nature. Consensus criteria for the distinction of these from the ordinary precursors of adenocarcinoma, the pancreatic intraepithelial neoplasia, were established. The definition of mucinous cystic neoplasms was refined; ovarian-like stroma has now become almost a requirement for the diagnosis of mucinous cystic neoplasia, and defined as such, the propensity of these tumors to occur in perimenopausal women became even more striking. The validity and clinical value of classifying the pancreatic cysts of mucinous type as adenoma, borderline, CIS and invasive have been established. Related to this, the importance of thorough sampling in accurate classification of these mucinous lesions was recognized. Greater accessibility of the pancreas afforded by improved invasive as well as noninvasive modalities has also increased the detection of otherwise clinically silent cystic tumors, which has led to the recognition of more innocuous entities such as acinar cell cystadenoma and squamoid cyst of pancreatic ducts. As the significance of the cystic lesions emerged, cystic forms of otherwise typically solid tumors were also better characterized. Thus, significant developments have taken place in the classification and our understanding of pancreatic cystic tumors in the past few years, and experience with these lesions is likely to grow exponentially in the coming years.

The purpose of our study was to determine useful CT criteria for differentiating serous oligocystic adenomas of the pancreas from other similarly presenting neoplasms, such as mucinous cystadenoma and intraductal papillary mucinous tumor of the branch duct type.

Forty-one patients with histologically confirmed macrocystic neoplasms of the pancreas were enrolled: serous oligocystic adenoma in 10 patients, mucinous cystadenoma in 13, and intraductal papillary mucinous tumor in 18. Location, greatest dimension, shape, presence of mural nodules, presence of wall calcification, and the extent and degree of main pancreatic duct (MPD) dilatation were analyzed with CT. The lesions were categorized into seven groups according to their shapes: multicystic, lobulated contour with and without internal septation, smooth contour with and without internal septation, pleomorphic cystic, and clubbed fingerlike cystic. Comparative studies were performed using Fisher's exact test and the Mann-Whitney U test.

Significant differences in lesion shape were found between serous oligocystic adenoma and the other macrocystic neoplasms (mucinous cystadenoma [p < 0.05], intraductal papillary mucinous tumor [p < 0.05]). Serous oligocystic adenoma had a multicystic or lobulated contour with or without septation, whereas mucinous cystadenoma had a smooth contour with or without septation and intraductal papillary mucinous tumor had either a pleomorphic or a clubbed fingerlike cystic shape. Serous oligocystic adenoma showed proximal MPD dilatation from the lesion, whereas intraductal papillary mucinous tumor showed distal or whole MPD dilatation (p < 0.05). No significant difference was apparent among the three diseases in terms of location, greatest dimension, or presence of calcification or mural nodules.

Serous oligocystic adenoma of the pancreas has characteristic CT findings that differentiate it from other cystic tumors. It appears as a multicystic or lobulated cystic lesion with septation.

A 72-year-old man was admitted to our hospital for investigation of jaundice. We made a preoperative diagnosis of macrocystic serous cystadenoma (SCA) of the pancreas, but did not perform palliative choledochojejunostomy because aspiration of the pancreatic cystic fluid caused the cysts to shrink and relieved the compressive stenosis of the common bile duct (CBD) during the operation. Frozen sections of the cyst wall taken by incision biopsy showed no signs of malignancy. Therefore, we performed fenestration of the cystic wall after fixing the inner epithelium of the cyst with 100% ethanol and aspirating the cystic fluid. Cholangiography after the cystic fenestration showed resolution of the CBD stenosis and abdominal computed tomography (CT) confirmed the disappearance of the pancreatic cysts. No recurrence of cystic swelling or obstructive jaundice has been detected by abdominal CT or laboratory data for more than 2 years since the cystic fenestration. Thus, cystic fenestration may be a better palliative option for treating benign compressive tumors such as macrocystic SCA of the pancreas causing obstructive jaundice.

The preoperative distinction between serous cystic neoplasms (SCNs) and mucinous cystic neoplasms (MCNs) is essential, as all MCNs are considered malignant or potentially malignant and should be surgically resected, whereas SCNs are almost always benign. However, the radiologic distinction between SCNs and MCNs is frequently difficult especially with serous oligocystic adenoma (SOA), a morphologic variant of SCN, as both SOA and MCN appear on cross-sectional imaging as a solitary macrocystic lesion in the pancreas. We reviewed all SOAs managed at our institution to determine if any clinicopathologic features would prove useful for establishing a preoperative diagnosis.

Over a 15-year period, 64 patients with a pathologically confirmed diagnosis of a pancreatic cystadenoma or cystadenocarcinoma treated at Singapore General Hospital were retrospectively reviewed. There were 27 MCNs and 37 SCNs including 12 SOAs. In addition, 40 cases of SOA previously reported in the literature were reviewed and analyzed together with the 12 patients, making this a series of 52 SOAs.

In our experience, SOAs comprised 32.4% of the SCNs, and females predominated (7/12). The median age of the patients was 42.5 years (range 22-74 years), and only 4 of the 12 patients were symptomatic. Most of the cysts were located in the body or tail of the pancreas (9/12), and the median cyst size was 52.5 mm (range 10-190 mm). When the clinicopathologic features of SOAs and serous microcystic adenomas (SMAs) were compared, there was no difference between the patients with SOAs and SMAs in terms of age, sex, presence of symptoms, cyst size, or site of the lesion. However, SOAs occurred in the women less frequently (67.3% vs. 96.3%, P=0.004), were smaller [40 mm (range 10-190 mm) vs. 95 mm (range 25-180 mm), P<0.001], and occurred more commonly in the head of the pancreas [25 (48.1%) vs. 2(7.4%)] compared to MCNs. None of the SOAs were frankly malignant compared to the 29.6% of MCNs that were.

SOAs and SMAs have similar clinicopathologic features. On the other hand, SOAs differ from MCNs by their relatively higher male/female ratio, higher frequency of tumors occurring in the head of the pancreas, and smaller cyst size. Knowledge of these distinguishing clinical features when used in combination with other diagnostic modalities such as endoscopic ultrasonography/fine-needle aspiration will enable clinicians to better differentiate these two pathologic entities preoperatively.

To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors.

Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4).

Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters < or = 2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed.

MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.

The differential diagnosis between macrocystic serous cystoadenoma and mucinous cystoadenoma is very difficult but is highly important due to the latter's potential for malignant transformation. We present a case of unilocular macrocystic serous cystoadenoma. Due to the impossibility of obtaining an accurate preoperative diagnosis, all macrocystic unilocular lesions, in an appropriate clinical context, must be resected.

To define the natural history and optimal management of serous cystadenoma of the pancreas.

Serous cystadenoma of the pancreas is the most common benign pancreatic neoplasm. Diagnostic criteria, potential for growth or malignancy, and outcomes are not well defined. As a result, management for patients with serous cystadenomas varies widely in current practice.

A total of 106 patients presenting with serous cystadenoma of the pancreas from 1976-2004 were identified. Hospital records were evaluated for patient and tumor characteristics, diagnostic workup, treatment, and outcome. Twenty-four patients with serial radiographic imaging were identified, and tumor growth curves calculated.

Mean age at presentation was 61.5 years and 75% of patients were female. The most common symptoms were abdominal pain (25%), fullness/mass (10%), and jaundice (7%); 47% were asymptomatic. Mean tumor diameter was 4.9 +/- 3.1 cm, which did not vary by location. Tumors <4 cm were less likely to be symptomatic than were tumors > or =4 cm (22% vs. 72%, P < 0.001). The median growth rate in the patients who had serial radiography was 0.60 cm/y. For tumors <4 cm at presentation (n = 15), the rate was 0.12 cm/y, whereas for tumors > or =4 cm (n = 9), the rate was 1.98 cm/y (P = 0.0002). Overall, 86 patients underwent surgery, with one perioperative death.

Large (>4 cm) serous cystadenomas are more likely to be symptomatic. Although the median growth rate for this neoplasm is only 0.6 cm/y, it is significantly greater in large tumors. Whereas expectant management is reasonable in small asymptomatic tumors, we recommend resection for large serous cystadenomas regardless of the presence or absence of symptoms.

Cystic tumors and tumor-like lesions of the pancreas are rare, but have attracted a great deal of attention because they are easily recognized with new imaging methods and, in contrast to ductal adenocarcinoma, they can usually be cured surgically. The increasing resection rate in recent years has also increased our knowledge of cystic pancreatic tumors by conspicuously enlarging their morphological spectrum. Known entities have been better characterized (i.e. solid pseudopapillary neoplasm, intraductal papillary mucinous neoplasm) and new ones described (serous oligocystic adenoma, mucinous non-neoplastic cyst, acinar cell cystadenoma and cystic hamartoma). This review discusses the most important cystic tumors and tumor-like lesions, presents a new classification, and summarizes the immunohistochemical differential diagnosis.

MR imaging is a valuable tool in the assessment of the full spectrum of pancreatic diseases. MR imaging techniques are sensitive for the evaluation of pancreatic disorders in the following settings: (1) TI-weighted fat-suppressed and dynamic gadolinium-enhanced SGE imaging for the detection of chronic pancreatitis, ductal adeno-carcinoma, and islet-cell tumors; (2) T2-weighted fat-suppressed imaging and T2-weighted breath-hold imaging for the detection of islet-cell tumors;and (3) precontrast breath-hold SGE imaging for the detection of acute pancreatitis. Relatively specific morphologic and signal intensity features permit characterization of acute pancreatitis,chronic pancreatitis, ductal adenocarcinoma, insulinoma, gastrinoma, glucagonoma, microcystic cystadenoma, macrocystic cystadenoma, and solid and papillary epithelial neoplasm. MR imaging is effective as a problem-solving modality because it distinguishes chronic pancreatitis from normal pancreas and chronic pancreatitis with focal enlargement from pancreatic cancer in the majority of cases.MR imaging studies should be considered in the following settings: (1) in patients with elevated serum creatinine, allergy to iodine contrast, or other contraindications for iodine contrast administration; (2) in patients with prior CT imaging who have focal enlargement of the pancreas with no definable mass; (3) in patients in whom clinical history is worrisome for malignancy and in whom findings on CT imaging are equivocal or difficult to interpret; and (4) in situations requiring distinction between chronic pancreatitis with focal enlargement and pancreatic cancer. Patients with biochemical evidence of islet-cell tumors should be examined by MR imaging as the first-line imaging modality because of the high sensitivity of MR imaging for detecting the presence of islet-cell tumors and determining the presence of metastatic disease.

Whereas mucinous cystadenomas of the pancreas are considered premalignant, serous cystadenomas are believed to remain benign. We present a case of an 80-year-old woman with a primary tumor of the pancreas that was histologically classified as serous cystadenocarcinoma. Because preoperatively available criteria that determine malignancy in serous lesions are lacking, observation is the preferred option in serous cystadenomas. Operating every serous lesion is not justified. Reviewing all reports of serous cystadenocarcinomas that have been published to date, we are providing recommendations for the management of this rare entity.

We report a case of serous cystadenoma of the pancreas mixed with mucinous cystadenoma. A 65-year-old woman was admitted to our hospital for evaluation of a palpable, elastic, hard mass measuring 6 cm in diameter in the right upper quadrant of the abdomen. A diagnosis of mucinous cystadenocarcinoma of the pancreas was made, and pancreatoduodenectomy was performed. The tumor was composed of a dominant compartment of macroscopic cyst, and its thick wall was filled with numerous microscopic cysts. The light microscopy findings with hematoxylin and eosin staining, and by the periodic acid-Schiff reaction, were almost perfectly consistent with the characteristics of microcystic or glycogen-rich cystadenoma, but the apical portion of the cytoplasm of the neoplastic cells was stained with Alcian blue at pH 2.4 and by the mucicarmine method. Neoplastic cells containing epithelial acidic mucin are usually found in mucinous cystadenomas. No K-ras point mutations were detected at the sites where neoplastic cells were present, whether or not they contained epithelial acidic mucin. Pancreatic serous cystadenomas that include a mucinous-cystadenoma component are extremely rare, and the difference between serous and mucinous cystadenomas is not always distinct.