Cystic lesions of the pancreas

Rare nonneoplastic cysts of pancreas

Pancreatic cysts represent a small proportion of pancreatic diseases, but their incidence has been recently increasing. Most pancreatic cysts are identified incidentally, causing a dilemma for both clinicians and patients. In contrast to ductal adenocarcinoma, neoplastic pancreatic cysts may be cured by resection. In general, pancreatic cysts are classified as neoplastic or non-neoplastic cysts. The predominant types of neoplastic cysts include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms, and solid pseudopapillary neoplasms. With the exception of serous type, neoplastic cysts, have malignant potential, and in most cases requires resection. Non-neoplastic cysts include pseudocyst, retention cyst, benign epithelial cysts, lymphoepithelial cysts, squamous lined cysts (dermoid cyst and epidermal cyst in intrapancreatic accessory spleen), mucinous nonneoplastic cysts, and lymphangiomas. The incidence of nonneoplastic, noninflammatory cysts is about 6.3% of all pancreatic cysts. Despite the use of high-resolution imaging technologies and cytologic tissue acquisition with endosonography, distinguishing nonneoplastic from neoplastic cysts remains difficult with most differentiations made postoperatively. Nonetheless, the definitive distinction between non-neoplastic and neoplastic cysts is crucial as unnecessary surgery could be avoided with proper diagnosis. Therefore, consideration of these rare disease entities should be entertained before deciding on surgery.

Clinical and radiological feature of lymphoepithelial cyst of the pancreas

A lymphoepithelial cyst (LEC) of the pancreas is a rare benign lesion. Because patients with LEC of the pancreas have a good prognosis, it is important that these lesions are accurately differentiated from other more aggressive pancreatic neoplasms for an appropriate treatment strategy. Previous studies have reported that a definitive diagnosis of LEC often cannot be obtained based solely on the findings of preoperative imaging (e.g., Computed tomography or Magnetic resonance imaging). In this study, we reviewed four cases of pancreatic LECs to investigate the feature of LECs. We reviewed these cases with regard to symptoms, imaging findings, surgical procedures, and other clinical factors. We found that LEC was associated with unique characteristics on imaging findings. A preoperative diagnosis of LEC may be possible by comprehensively evaluating its clinical and imaging findings.

Solid pancreatic tumors with unilocular cyst-like appearance on CT: differentiation from unilocular cystic tumors using CT

Objective

To describe the computed tomography (CT) features of neuroendocrine tumors (NETs) and solid pseudopapillary tumors (SPTs) with unilocular cyst-like appearance, and to compare them with those of unilocular cystic tumors of the pancreas.

Materials and Methods

This retrospective study was approved by our Institutional Review Board, and informed consent was waived. We included 112 pancreatic tumors with unilocular cyst-like appearance on CT (16 solid tumors [nine NETs and seven SPTs] and 96 cystic tumors [45 serous cystadenomas, 30 mucinous cystic neoplasms, and 21 branch-duct intraductal papillary mucinous neoplasms]). Two radiologists reviewed the CT images in consensus to determine tumor location, long diameter, morphological features, wall thicknesses, ratio of wall thickness to tumor size, wall enhancement patterns, intratumoral contents, and accompanying findings. Fisher's exact test was used to analyze the results.

Results

All 16 solid tumors had perceptible walls (mean thickness, 2.7 mm; mean ratio of wall thickness to tumor size, 7.7%) with variable enhancement. Four NETs and seven SPTs had hemorrhage, calcifications, and/or mural nodules. Six CT findings were specific for solid tumors with unilocular cyst-like appearance: a thick (> 2 mm) wall, uneven thickness of the wall, high ratio of wall thickness to tumor size, hyper- or hypo-attenuation of the wall in the arterial and portal phase, and heterogeneous internal contents. When three or more of the above criteria were used, 100% specificity and 87.5-92% accuracy were obtained for solid tumors with unilocular cyst-like appearance.

Conclusion

A combination of CT features was useful for distinguishing solid tumors with unilocular cyst-like appearance from unilocular cystic tumors of the pancreas.

Squamoid cystosis of pancreatic ducts: a variant of a newly-described cystic lesion, with evidence for an obstructive etiology

We describe a 40-year-old man who was found to have a cystic mass in the pancreatic tail during workup for weight loss and abdominal discomfort. Although computed tomography scan showed a single cyst associated with dilatation of the main pancreatic duct, gross and histologic examination of the distal pancreatectomy specimen actually revealed a central cyst that was surrounded by multiple smaller cystic spaces. This distinctive appearance was formed from extensive cystic dilatation and squamous metaplasia of the native pancreatic duct system. Further, a traumatic neuroma was discovered near the junction between normal and abnormal parenchyma. We believe that this case represents a variant of the newly-described squamoid cyst of pancreatic ducts which we term squamoid cystosis of pancreatic ducts. The presence of chronic pancreatitis and a traumatic neuroma supports the hypothesis that squamoid cysts are non-neoplastic lesions arising from prior duct obstruction.

Proteomic mucin profiling for the identification of cystic precursors of pancreatic cancer

BACKGROUND

Pancreatic cystic lesions (PCLs) are increasingly frequent radiological incidentalomas, with a considerable proportion representing precursors of pancreatic cancer. Better diagnostic tools are required for patients to benefit from this development.

METHODS

To evaluate whether cyst fluid mucin expression could predict malignant potential and/or transformation in PCLs, a proteomic method was devised and prospectively evaluated in consecutive patients referred to our tertiary center for endoscopic ultrasound-guided aspiration of cystic lesions from May 2007 through November 2008 (discovery cohort) and from December 2008 through October 2012 (validation cohort). Cytology and cyst fluid carcinoembryonic antigen (CEA; premalignancy > 192 ng/mL, malignancy > 1000 ng/mL) were routinely analyzed, and samples were further processed as follows: one-dimensional gel electrophoresis, excision of high-mass areas, tryptic digestion and nano-liquid chromatography-tandem mass spectrometry, with peptide identification by Mascot software and an in-house mucin database. All diagnostic evaluations were blinded to proteomics results. Histology was required to confirm the presence/absence of malignant transformation. All statistical tests were two-sided.

RESULTS

Proteomic mucin profiling proved statistically significantly more accurate (97.5%; 95% confidence interval [CI] = 90.3% to 99.6%) than cytology (71.4%; 95% CI = 59.8% to 80.9%; P < .001) and cyst fluid CEA (78.0%; 95% CI = 65.0% to 87.3%; P < .001) in identifying the 37 (out of 79; 46.8%) lesions with malignant potential (ie, premalignant or malignant tumors). The accuracy of proteomics was nearly identical (96.6% vs 98.0%) between the discovery (n = 29) and validation (n = 50) cohorts. Furthermore, mucin profiling predicted malignant transformation, present in 16 out of 29 (discovery cohort: 9, validation cohort: 20) lesions with available histology, with 89.7% accuracy (95% CI = 71.5% to 97.3%) (for the validation cohort only: 95.0%; 95% CI = 73.1% to 99.7%). This markedly exceeded corresponding results for cytology (51.7%; 95% CI = 32.9% to 70.1%; P = .003) and CEA (57.1%; 95% CI = 34.4% to 77.4%; P = .02).

CONCLUSIONS

Proteomic cyst fluid mucin profiling robustly discriminates benign, premalignant, and malignant PCLs. Consequently, it may improve pancreatic cancer prevention and reduce the morbidity burden of unwarranted pancreatic surgery.

Non-neoplastic epithelial cysts of the pancreas: a rare, benign entity

OBJECTIVES

With the increased use of cross-sectional radiologic imaging in recent years, cystic lesions of the pancreas are being diagnosed with greater frequency. While pseuodocysts have historically accounted for the majority of benign pancreatic cysts, there are a number of rare, benign cystic lesions of the pancreas that can mimic neoplastic cysts. The objective of this study was to review a single institution's experience with these benign cystic lesions of the pancreas.

METHODS

We conducted a retrospective analysis of all patients who underwent surgical resection for pancreatic disease from 2005 to 2012 at our institution. Out of a total of 947 pancreatic resections, we identified those cases performed for cystic disease, and focused upon the clinicopathologic data of patients with non-neoplastic pancreatic cysts.

RESULTS

Of the 947 pancreatic resections, 256 (27%) were performed for cystic disease. Sixteen cases (6.3%) out of the total of 256 pancreatic operations performed for cystic disease were found to have non-neoplastic cystic lesions of the pancreas. Preoperative imaging revealed primary lesions in all patients, eight of which were found incidentally. Of these lesions, 14 were suspected preoperatively to be mucinous neoplasms and two to harbor pancreatic adenocarcinoma. However, postoperative pathology revealed eight patients with ductal retention cysts, three squamoid cysts, one mucinous non-neoplastic cyst, one congenital ciliated foregut cyst, one lymphoepithelial cyst, and two endometrial cysts. Two patients had complications postoperatively, one pancreatic fistula and one SMV thrombosis. Both complications resolved with conservative management.

CONCLUSIONS

Non-neoplastic epithelial pancreatic cysts are rare, benign lesions. In our institutional experience, these lesions are often indistinguishable from cystic neoplasms of the pancreas preoperatively. As such, many of these lesions are resected unknowingly. It is important for the clinician to be well informed of the nature of these lesions, in the hopes to avoid unnecessary resection whenever possible.

Pancreatic cysts: etiology, diagnosis and management

Pancreatic cysts involve a wide spectrum of pathologies from post-inflammatory cysts to malignant neoplasms. Pancreatic pseudocysts, serous cystadenomas, mucinous cystadenomas, intraductal papillary mucinous neoplasms (IPMNs) and solid pseudopapillary tumors occur most frequently. Differential diagnosis involves the following imaging investigations: transabdominal ultrasonography (TUS), contrast enhanced ultrasonography (CEUS) and endoscopic ultrasonography (EUS), computed tomography (CT), magnetic resonance (MR) and magnetic resonance cholangiopancretography (MRCP), endoscopic retrograde cholangiopancretography (ERCP). The cyst fluid cytology is performed in difficult differential diagnosis between pseudocysts and benign and potentially malignant or malignant tumors. Most frequently, viscosity, amylase, CEA and CA 19-9 levels are determined. Imaging findings should be correlated with cytology. The management depends on the cyst type and size. Small asymptomatic pseudocysts, serous cystadenomas and branchduct IPMNs should be carefully observed, whereas symptomatic large or uncertain serous cystadenomas and cystadenocarcinomas, mucinous cystadenomas and cystadenocarcinomas, main-duct IPMNs and large branch-duct IPMNs with malignant features, serous and mucinous cystadenocarcinomas, and solid pseudopapillary tumors require surgery. Pseudocysts are usually drained. Percutaneous / EUS-guided or surgical cyst drainage can be performed. Complicated and uncertain pseudocysts and cystic tumors need surgical resection. The type of surgery depends on cyst location and size and includes proximal, central, distal, total pancreatectomies and enucleation.

Fine needle aspiration cytology of acinar cell cystadenoma of the pancreas

BACKGROUND

Acinar cell cystadenoma (ACC) is a recently recognized cystic lesion of the pancreas that demonstrates acinar differentiation and is currently believed to behave in a benign fashion. ACC enters the differential diagnosis of pancreatic cystic lesions alongside better recognized entities such as mucinous cystic and intraductal papillary mucinous neoplasms. Although uncommon, patients with ACC can undergo fine needle aspiration (FNA) of the lesion. However, the diagnosis is rarely made on cytologic examination due to sparse cellularity. Furthermore, the eosinophilic amorphous material in the cyst lumen may be mistaken for mucin, resulting in an incorrect diagnosis of a mucinous cyst. To date, there is a paucity of literature on the cytomorphology of ACC, both in peer-reviewed publications and cytopathology texts.

CASE

To our knowledge, we present the first detailed case report of FNA of ACC in a 22-year-old asymptomatic female. The FNA cytology specimen was hypocellular, and the presence of amorphous secretions led to the initial diagnosis of a mucinous-type neoplasm. Following surgical resection, the cytology specimen was reviewed.

CONCLUSION

We discuss the cytomorphologic features of ACC along with the potential pitfalls and diagnostic implications.

A review of pancreatic cyst fluid analysis in the differential diagnosis of pancreatic cyst lesions

Diagnosis and management of pancreatic cyst lesions is challenging as there is currently no investigation that offers both high diagnostic sensitivity and high specificity for the identification of potentially malignant lesions. Accurate classification of these lesions is vital in order to avoid unnecessary treatment of benign lesions and missed opportunities for early treatment of lesions that are malignant/pre-malignant. Pancreatic cyst fluid analysis has an important role in diagnosis, although all currently available investigations based on fluid analysis have significant limitations. Cytological analysis can reveal features that are specific for a certain class of cyst, but offers limited sensitivity in detecting malignant/pre-malignant cysts. Measurement of tumour markers, particularly carcinoembryonic antigen can also be informative. Concentrations of cyst fluid carcinoembryonic antigen tend to be higher in malignant/pre-malignant cysts, although there is a wide overlap between the various classes of cyst. A number of studies have suggested that diagnostic carcinoembryonic antigen cut-offs can be chosen that provide a high degree of specificity but limited sensitivity. Studies of the analytical validity of tumour marker assays in pancreatic cyst fluid analysis have highlighted discrepancies in some fluid specimens, which require further investigation. DNA analysis also has a role. In particular, K-Ras-2 mutational analysis appears to provide high specificity for detection of malignant/pre-malignant lesions. A number of diagnostic algorithms have been published, integrating use of available investigations in order to achieve the optimum discrimination of benign and potentially malignant cysts. Research into new biochemical markers and optimal use of available pancreatic cyst fluid analyses is ongoing.

Two rare cases of a solid pseudopapillary neoplasm of the pancreas

A solid pseudopapillary neoplasm (SPN) of the pancreas has distinct histopathological features. A solid pattern of growth with pseudopapillary structures that result from degeneration is observed. On rare occasions, the tumor may vary from being entirely solid to completely cystic. The present study describes two unique cases of SPN. A 25-year-old male presented with a pancreatic tumor showing a predominantly solid pattern with no degenerative change, although the pre-operative cytological specimens that were obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) revealed pseudopapillary structures. The second case was of an 11-year-old female who presented with a pancreatic tumor with prominent degeneration. Nests and cords of the remaining neoplastic cells were located only at the periphery, with perineural invasion. An immunohistochemical analysis revealed that the tumor cells in the two cases were positive for CD10 and β-catenin and negative for trypsin. An awareness of the broad morphological variability of SPN and an immunohistochemical panel that includes CD10, β-catenin and trypsin are useful for establishing an accurate diagnosis.

Pancreatic mucinous cystic neoplasm with sarcomatous stroma metastasizing to liver: a case report and review of literature

We report a case of mucinous cystic neoplasm of pancreas with sarcomatous stroma metastasizing to the liver. The tumor occurred in a male patient aged 46 years. Symptoms included persistent epigastric and right upper quadrant pain. Radiographically, the pancreas contained four large cystic masses located in the neck, body, and tail. Histologically, the cysts were lined with benign, mucinous epithelium with underlying bland, storiform, ovarian-like stroma. An undifferentiated focally hyalinized, sarcomatous stroma composed of bland spindle cells showing short fascicular growth pattern and focal nuclear palisading was associated with the epithelial component in one of the cysts. These cells showed strong immunoreactivity with vimentin and inhibin (weak), they were negative for CD34, estrogen receptor, progesterone receptor, androgen, calretinin, S-100, CD117, melan A, chromogranin, and synaptophysin. A morphologically and immunohistochemically identical metastatic sarcomatous focus was identified in the liver without any glandular component. This case is unique in its clinically malignant behaviour and metastatic nature despite its morphologically benign epithelial and stromal components.

Acinar cystadenoma of the pancreas: a clinicopathologic study of 10 cases including multilocular lesions with mural nodules

Pancreatic acinar cystadenomas (ACAs) are rare cystic lesions showing acinar differentiation with benign outcome. Although debated, ACAs are favored to be neoplastic and potentially the benign counterpart of acinar cystadenocarcinoma. We present the largest single institution series to date comprising 10 cases. The mean age was 49 years with a female predominance (M:F=1:2.3). Abdominal/flank pain was the most common presentation (n=6). Serum amylase/lipase and cyst fluid amylase were often elevated. All lesions had a benign outcome on follow-up (5 to 67 mo). The lesions were unilocular (n=3) or multilocular (n=7) with mean size of 3.8 cm (range, 2.9 to 5.0 cm) and 5.1 cm (range, 2.0 to 7.5 cm), respectively. Eight lesions were unifocal with locations as follows: head (n=2), head/neck (n=2), body (n=1), tail (n=1), predominantly extrapancreatic with a microscopic intrapancreatic component (n=1), and unspecified location (n=1). Two lesions were multifocal, involving the head/uncinate/body and pancreatic head, respectively. Two aspects of ACAs that may represent a diagnostic pitfall include the propensity for acinar epithelium to appear as nondescript flat/cuboidal epithelium (trypsin/chymotrypsin immunopositive) and epithelial heterogeneity, with focal mucinous and squamous epithelium, the latter particularly in multilocular variants. In addition, 2 cases with intracystic nodules were observed. Array comparative genomic hybridization performed on 1 of these cases showed multiple chromosomal gains involving 1p, 3p, 5q, 6p, 7q, 8, 10q, 11, 14, 20, and X. These findings provide preliminary evidence that ACAs represent a cystic neoplastic lesion.

Immunohistochemical features of the gastrointestinal tract tumors

Gastrointestinal tract tumors include a wide variety of vastly different tumors and on a whole are one of the most common malignancies in western countries. These tumors often present at late stages as distant metastases which are then biopsied and may be difficult to differentiate without the aid of immunohistochemical stains. With the exception of pancreatic and biliary tumors where there are no distinct immunohistochemical patterns, most gastrointestinal tumors can be differentiated by their unique immunohistochemical profile. As the size of biopsies decrease, the role of immunohistochemical stains will become even more important in determining the origin and differentiation of gastrointestinal tract tumors.

Primary pancreatic cystic neoplasms of the pancreas revisited. Part IV: rare cystic neoplasms

Primary pancreatic cystic neoplasms are being recognized with increasing frequency due to modern imaging techniques. In addition to the more common cystic neoplasms-serous cystadenoma, primary mucinous cystic neoplasm, and intraductal papillary mucinous neoplasm-there are many other less common neoplasms that appear as cystic lesions. These cystic neoplasms include solid pseudopapillary neoplasm of the pancreas (the most common rare cystic neoplasm), cystic neuroendocrine neoplasm, cystic degeneration of otherwise solid neoplasms, and then the exceedingly rare cystic acinar cell neoplasm, intraductal tubular neoplasm, angiomatous neoplasm, lymphoepithelial cysts (not true neoplasms), and few others of mesenchymal origin. While quite rare, the pancreatic surgeon should at the least consider these unusual neoplasms in the differential diagnosis of potentially benign or malignant cystic lesions of the pancreas. Moreover, each of these unusual neoplasms has their own natural history/tumor biology and may require a different level of operative aggressiveness to obtain the optimal outcome.

Invasive mucinous cystic neoplasms of the pancreas

Mucinous cystic neoplasms (MCN) and intraductal papillary mucinous neoplasms (IPMN) of the pancreas both appear to have been included and intermixed in some early reports of pancreatic cystic neoplasms. Recognition of their distinguishing features evolved during the last decade of the twentieth century. One legacy of the early period is the statement that mucinous cystic neoplasms sometimes progress to invasive colloid carcinoma. It is now recognized that colloid carcinomas characteristically arise from IPMN. We set out to see if we could find MCN that invaded as colloid carcinomas and found no examples in MCN collected in two academic medical centers. We then sought to expand the number of MCN by evaluating series from additional centers. This yielded no examples of colloid carcinomas associated with 291 MCN, however one MCN exhibited a minor component with colloid (non-cystic mucinous) growth pattern within the fibrous wall of the neoplasm. The expression of CDX2, a marker of intestinal differentiation that is found in colloid carcinomas was examined by immunostaining in the original MCN series and in the MCN with the intratumoral colloid growth pattern. Focal expression of CDX2 was found in 22 of 43 MCN including the MCN that exhibited the intratumoral colloid growth pattern. Overall, the data suggest that MCN rarely, if ever, invade as colloid carcinoma but the expression of CDX2 by some MCN and the observation of intratumoral colloid growth pattern in one MCN seems to leave open the possibility that MCN might rarely invade as colloid carcinoma. The majority of malignant MCN invade with a tubular (ductal) pattern, and rarely the invasive component was anaplastic.

A noninvasive mucinous cystic neoplasm with intermediate-grade dysplasia of the pancreas and extensive squamous metaplasia: a case report with clinicopathological correlation

Abstract

Squamous metaplasia presenting in noninvasive mucinous cystic neoplasm (MCN) of the pancreas is extremely rare. We described a case of 39-year-old Chinese female with a 5-year history of a slow growing mass in the left upper abdomen and an 18-month history of surgical incision exudation. The patient underwent cystojejunostomy, laparotomy and distal pancreatectomy consecutively because of the initial diagnosis of “pancreatic cyst”. The histological section showed columnar mucin-producing epithelium formed small papillary projections and extensively visible squamous metaplasia. Therefore the diagnosis of “noninvasive MCN with intermediate-grade dysplasia of the pancreas and extensive squamous metaplasia” was made finally. The squamous component of the pancreas may be derived from pluripotent stem cells, and may be in association with cystojejunostomy.

Virtual slides

The virtual slide(s) for this article can be found here http://www.diagnosticpathology.diagnomx.eu/vs/1322364365718540

The clinical significance of "squamous intraepithelial lesion of indeterminate grade" as a distinct cytologic category

The histologic and/or cytologic follow-up of 127 cases of cervical lesions termed "squamous intraepithelial lesion of indeterminate grade" (SIL) on Papanicolaou (Pap) smears by the 2001 Bethesda System was compared with 150 control cases of low-grade SIL (LSIL), high-grade SIL (HSIL), and atypical squamous cells, cannot exclude HSIL (ASC-H). A follow-up diagnosis of cervical intraepithelial neoplasia (CIN) 2 or higher was identified in 22.8% of SIL cases, which was 2.6 times higher than LSIL, 3 times lower than HSIL, and 1.5 times lower than ASC-H. A follow-up diagnosis of CIN 1 was identified in 31.5% of SIL cases, which was 2 times lower than the LSIL group, 1.5 times higher than the ASC-H cases, and 1.8 times higher than the HSIL group. We found that 22.0% of cases diagnosed as SIL were followed up by Pap smears rather than colposcopy and biopsy, compared with about 1% of LSIL and HSIL cases. Because SIL cases have a significant risk of harboring CIN 2 or greater, we recommend follow-up by colposcopy and biopsy.

Malignant potential in incidental pancreatic cysts

Although pancreatic cysts are being diagnosed with greater frequency, a uniform agreement on management is still lacking. This is mainly because accurate and reliable preoperative determination of the exact pathology of a pancreatic cyst remains elusive. Although ultrasound-guided fine needle aspiration represents a significant advancement in our ability to characterize pancreatic cysts preoperatively, significant limitations persist. In this article, we review the roles of clinical characteristics, imaging features and biochemical markers in the correct classification of incidental pancreatic cysts. The correct diagnosis and management of these cysts still hinges, to a large extent, on clinical experience and multidisciplinary cooperation.

Diagnostic and radiological management of cystic pancreatic lesions: important features for radiologists

Cystic pancreatic neoplasms are often an incidental finding, the frequency of which is increasing. The understanding of such lesions has increased in recent years, but the numerous types of lesions involved can hinder differential diagnosis. They include, in particular, intraductal papillary mucinous neoplasms (IPMN), serous cystic neoplasms (SCN), and mucinous cystic neoplasms (MCN). Knowledge of their histological and radiological structure, as well as distribution in terms of localization, age, and sex, helps to differentiate such tumours from common pancreatic pseudocysts. Several types of cystic pancreatic neoplasms can undergo malignant transformation and, therefore, require differentiated radiological management. This review aims to develop a broader understanding of the pathological and radiological characteristics of cystic pancreatic neoplasms, and provide a guideline for everyday practice based on current concepts in the radiological management of the given lesions.

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

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

[Precursor lesions of pancreatobiliary cancer]

Precursor lesions of pancreatobiliary cancer can be divided into cystic and flat lesions. Mucinous cystic neoplasm and intraductal papillary mucinous neoplasm (IPMN) comprise the cystic precursors in the pancreas, while intraductal papillary neoplasm (IPN) represents their counterpart in the bile duct system. There is an adenoma-carcinoma sequence in the cystic precursors arising from four different types of epithelia: pancreatobiliary, oncocytic, intestinal and gastric. These subtypes of IPMN/IPN are morphologically and immunohistochemically well characterised and show clinical and prognostic relevance: the gastric subtype is associated with the best prognosis, followed by the oncocytic and intestinal subtypes, while the pancreatobiliary subtype is characterized by adverse clinical behaviour. Pancreatic intraepithelial neoplasia (PanIN) and biliary intraepithelial neoplasia (BilIN) represent the flat precursors. PanIN are morphologically and biologically well defined. PanIN with lobulocentric atrophy has recently been described as a putative precursor of pancreatic cancer. Despite well defined morphological features in BilIN, the molecular alterations seen during early tumor progression in the biliary tract are poorly understood.

Intraductal papillary mucinous neoplasms of the pancreas--a surgical disease

Cystic pancreatic neoplasms are increasingly recognized, with intraductal papillary mucinous neoplasms of the pancreas (IPMNs) being the most frequently observed type. IPMNs are characterized by mucin production and epithelial growth within the pancreatic ducts, and are generally differentiated according to location: main pancreatic duct, its major side branches, or both (mixed type). IPMNs vary from benign to malignant and are considered precursor lesions of pancreatic adenocarcinoma. However, the exact time to neoplastic transformation and whether all IPMNs progress to malignant tumors is unclear. Surgical resection is warranted for all main-duct and mixed-type IPMNs (they harbor a high risk of malignancy of ~70%). By contrast, branch-duct IPMNs progress to cancer in only ~30% of cases. Thus, according to current guidelines (Sendai criteria), asymptomatic side-branch IPMNs <3 cm in size without suspicious radiological features (such as size progression) can be treated conservatively. Lately, even this approach has become controversial, owing to a number of Sendai-negative IPMNs showing malignant transformation. Although most IPMNs should be resected by standard oncological procedures (including lymphadenectomy), small Sendai-negative IPMNs can be treated with limited resections. This Review summarizes current knowledge of the treatment of IPMNs, with a particular focus on surgical approaches to this disease.

Large duct type invasive adenocarcinoma of the pancreas with microcystic and papillary patterns: a potential microscopic mimic of non-invasive ductal neoplasia

A morphological variant of pancreatic ductal adenocarcinoma forming large ductal elements, large duct type ductal adenocarcinoma, is documented and its clinicopathological features are studied. These tumors may have microcystic and papillary growth patterns that closely mimic the non-invasive cystic and papillary pancreatic tumors such as: intraductal papillary-mucinous neoplasia, including the oncocytic variant, mucinous cystic neoplasms, and ducts involved by pancreatic intraepithelial neoplasia. In a review of 230 pancreatectomy specimens with ductal adenocarcinoma, 28 (8%) cases of large duct type ductal adenocarcinomas were identified according to following criteria: more than 50% of the tumor sections available for examination contained infiltrative ducts with a diameter larger than 0.5 mm or had a macroscopically identifiable microcystic pattern. Overall characteristics of large duct type ductal adenocarcinomas were not too different than those of conventional ductal adenocarcinomas, except that there was a slight female predominance in the former (F/M=2.3). The mean age was 67 (vs 63 in conventional ductal adenocarcinomas; P=0.015), and occurrence in the tail was slightly more common (40% vs 18% in conventional ductal adenocarcinomas; P=0.006). Grossly, cysts measuring up to 1 cm was noted in 10 cases. Microscopically, large duct type adenocarcinomas were characterized by irregularly distributed large ducts with jagged edges, lined by columnar mucinous cells often having deceptively bland cytological features and variable degrees of papillomatosis. Stromal desmoplasia had a hypercellular quality (morphologically distinct from ovarian-like stroma) in four cases, and had a myxoid quality in others. KRAS oncogene mutation was identified in 9 out of 11 cases. Median, 1-year and 2-year survival rates were 16 months, 77% and 30%, respectively, as opposed to 12 months, 52% and 30%, respectively, in conventional ductal adenocarcinoma. In conclusion, it should be recognized that, some (8%) pancreatic ductal adenocarcinomas exhibit a large duct pattern that may microscopically mimic non-invasive pancreatic tumors characterized by cystic and papillary patterns. They may be distinguished by the relatively smaller size of the cysts, irregularity of the duct contours, clustering of the ducts, presence of intraluminal neutrophils and granular debris, degree of cytological pleomorphism, and myxoid quality of the stroma. Clinical behavior appears to be slightly better than that of conventional ductal adenocarcinoma, which may be accounted by the well-differentiated nature of these tumors.

Association between lymphoepithelial cysts of the pancreas and HIV infection

BACKGROUND & AIMS

To report the association of lymphoepithelial cysts (LEC) of the pancreas with Human Immunodeficiency Virus (HIV) infection. An association between LEC and HIV infection is already established in the parotid gland (PG).

METHODS

Report of the first two cases of LEC of the pancreas associated with HIV infection and comparison of the clinical and histopathological aspects of LECs of the pancreas and of the PG.

RESULTS

LECs of the pancreas were discovered by CT imaging in 2 patients with a history of HIV infection. Notably, LEC completely resolved in one patient after initiation of antiretroviral therapy.

CONCLUSION

This is the first report of an association of LEC of the pancreas and HIV infection. In the presence of LEC of the pancreas, we propose a systematic screening for HIV infection and associated lesions in the PG. Antiretroviral therapy should be initiated in untreated patients. Surgery should be reserved for symptomatic patients in whom medical therapy has failed.

Cyst fluid carcinoembryonic antigen is an accurate diagnostic marker of pancreatic mucinous cysts

OBJECTIVES

Endoscopic ultrasound (EUS) may offer a diagnostic tool through the combination of imaging and guided fine-needle aspiration of pancreatic cysts. The purpose of this investigation was to determine the most accurate test for differentiating mucinous from nonmucinous cysts.

METHODS

The results of EUS imaging, cytology, and cyst fluid biochemical markers were prospectively collected and compared in a large single-center study (776 patients) using histology or malignant cytology as the final diagnostic standard in 198 patients.

RESULTS

The mean cyst fluid carcinoembryonic antigen (CEA) was greater in mucinous cysts (4703.0 ng/mL) compared with nonmucinous cysts (25.8 ng/mL) (P = 0.008). When using the optimal cutoff value of 109.9 ng/mL, the CEA was more accurate (86%, receiver operating characteristic area = 0.928) than EUS imaging (48%) and cytology (58%) in predicting a mucinous cyst (P < 0.0001). Malignant cysts had a mean cyst fluid CEA value (2558.2 ng/mL) similar to benign cysts (4700.2 ng/mL). Cytology (75%) more accurately diagnosed malignant cysts than EUS (66%) and CEA (62%) (P < 0.05).

CONCLUSIONS

Cyst fluid CEA concentration provides a highly accurate test for the diagnosis of a mucinous cyst, but does not distinguish benign from malignant cysts. Cytology is the most accurate test for the diagnosis of a malignant cyst.

Solid tumors of the pancreas can put on a mask through cystic change

Background

Solid pancreatic tumors such as pancreatic ductal adenocarcinoma (PDAC), solid pseudopapillary tumor (SPT), and pancreatic endocrine tumor (PET) may occasionally manifest as cystic lesions. In this study, we have put together our accumulated experience with cystic manifestations of various solid tumors of the pancreas.

Methods

From 2000 to 2006, 376 patients with pancreatic solid tumor resections were reviewed. Ten (2.66%) of these tumors appeared on radiological imaging studies as cystic lesions. We performed a retrospective review of medical records and pathologic findings of these 10 cases.

Results

Of the ten cases in which solid tumors of the pancreas manifested as cystic lesions, six were PDAC with cystic degeneration, two were SPT undergone complete cystic change, one was cystic PET, and one was a cystic schwannoma. The mean tumor size of the cystic portion in PDAC was 7.3 cm, and three patients were diagnosed as 'pseudocyst' with or without cancer. Two SPT were found incidentally in young women and were diagnosed as other cystic neoplasms. One cystic endocrine tumor was preoperatively suspected as intraductal papillary mucinous neoplasm or mucinous cystic neoplasm.

Conclusions

Cystic changes of pancreas solid tumors are extremely rare. However, the possibility of cystic manifestation of pancreas solid tumors should be kept in mind.

Pancreatic Cystic Tumors of Mucinous Type

This article presents the clinicopathologic characteristics and differential features of pancreatic mucinous tumors. These tumors, which correspond to the most frequent cystic neoplasms, are encountered with increasing frequency. They comprise the mucinous cystic neoplasms and the intraductal papillary mucinous neoplasms. These tumors are known to progress from dysplasia to invasive carcinoma. Thus, it appears important to distinguish them from other cystic neoplasms and non-neoplastic cysts.

Molecular characteristics and biological behaviours of the oncocytic and pancreatobiliary subtypes of intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasm (IPMN) consists of four epithelial subtypes. Of those, pancreatobiliary and oncocytic types are recently recognized and relatively uncommon, and usually exhibit high-grade dysplasia. The biological properties and molecular characteristics of these two types have not been well documented. The few molecular studies of the oncocytic type showed absence of KRAS mutations commonly seen in the other subtypes, raising the possibility that the oncocytic type is distinct from the other subtypes. Thus, we examined clinicopathological features and molecular alterations of the two subtypes. The study cohort consisted of 12 pancreatobiliary and 18 oncocytic IPMN cases. KRAS, BRAF, and PIK3CA mutations and TP53, SMAD4, and β-catenin expression were analysed, and the results of molecular and clinicopathological profiles were compared between the two subtypes. KRAS mutations were identified in the oncocytic type, but less frequently than the pancreatobiliary type (17% versus 58%, p = 0.048). BRAF mutation was found in a single oncocytic tumour, and no PIK3CA mutations were seen in any of the study cohort. TP53 overexpression was less frequent in the oncocytic type than in the pancreatobiliary type (11% versus 58%, p = 0.013). Invasive components were present in 50% of the oncocytic and 92% of the pancreatobiliary types, with lymph node metastasis more frequently seen in the latter, corresponding to better outcomes in the former (5-year survival rates: 93% versus 32%, p = 0.014). Our demonstration of KRAS and BRAF mutations in the oncocytic-type IPMN supports a role for the activation of the RAS-MAPK pathway in this tumour type. However, the less frequent TP53 overexpression associated with the significantly lower rates of invasion and nodal disease in the oncocytic type correlates with better outcomes compared to the pancreatobiliary type.

Pancreatic endocrine tumors: radiologic-clinicopathologic correlation

Pancreatic endocrine tumors (PETs) are primarily well-differentiated tumors composed of cells that resemble normal islet cells but that arise from pancreatic ductal cells. They are classified as functioning or nonfunctioning according to their associated clinical symptoms; insulinoma, gastrinoma, and glucagonoma are the most common functioning PETs. They also are classified according to their biologic behavior, although all PETs have malignant potential. Most are sporadic, but some are associated with familial syndromes such as multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, and neurofibromatosis type 1. At imaging, PETs typically appear as well-defined hypervascular masses, a finding indicative of their rich capillary network. Cystic change, calcification, and necrosis are common in large tumors, which are associated with a poorer prognosis and a higher prevalence of local and vascular invasion and metastases than are smaller tumors. Even when metastases are present, many well-differentiated PETs have an indolent course. Poorly differentiated PETs are rare and have an infiltrative appearance; patients with such tumors have a poor prognosis. Knowledge of the characteristic clinical, pathologic, and radiologic features of PETs is important in the evaluation and management of patients with a suspected clinical syndrome or a pancreatic mass.

Pancreatic mucinous cystic neoplasm of the main pancreatic duct

Mucinous cystic neoplasm and intraductal papillary mucinous neoplasm are 2 types of cystic pancreatic mucinous tumors, each with its own distinct clinicopathologic features and pathogenetic mechanisms. We report here an unusual pancreatic mucinous neoplasm with features of both a mucinous cystic neoplasm and an intraductal papillary mucinous neoplasm in a 40-year-old woman who underwent total pancreatectomy. The endoscopic retrograde cholangiopancreatogram and gross examination demonstrated a mucin-producing intraductal neoplasm involving the length of the main pancreatic duct, typical of main duct intraductal papillary mucinous neoplasm, but histology of the main duct showed involvement by a biphasic tumor composed of columnar epithelium overlying ovarian-type stroma, characteristic of a mucinous cystic neoplasm. Immunohistochemistry confirmed that the stromal cells expressed estrogen and progesterone receptors, inhibin, and calretinin. Pancreatic mucinous cystic neoplasm involving the entire main pancreatic duct has not, to our knowledge, been previously reported.

Cystic lymphangioma of the pancreas with congenital intrahepatic duct dilatation and choledochal cyst

Cystic lymphangioma of the pancreas is an extremely rare benign tumor of lymphatic origin. We report on a 68-year-old woman who had experienced epigastric abdominal distension and nausea for over 1 year. Sonography revealed a cystic-solid mixed mass in the head of pancreas, with intrahepatic and extrahepatic duct dilatation. A diagnosis of cystic lymphangioma with congenital intrahepatic duct dilatation and choledochal cyst was made after excision and pathologic examination. Preoperative diagnosis of cystic lymphangioma of the pancreas is difficult, and carefulsonographic evaluation is required.

Acinar cell cystadenoma (acinar cystic transformation) of the pancreas: the radiologic-pathologic features

Acinar cystic transformation of the pancreas is also known as acinar cell cystadenoma (ACC), and this is an extremely rare benign lesion that was first described in April 2002. We report here on a case of a previously asymptomatic patient with pancreatic ACC and this was diagnosed by computed tomography (CT) and magnetic resonance imaging (MRI). To the best of our knowledge, there is no previous report concerning the CT or MRI features of ACC in the medical literature. We present here the CT, MRI and pathological findings of pancreatic ACC.

Management of mucinous cystic neoplasms of the pancreas

The purpose of this study was to investigate the actual management of mucinous cystic neoplasm (MCN) of the pancreas. A systematic review was performed in December 2009 by consulting PubMed MEDLINE for publications and matching the key words “pancreatic mucinous cystic neoplasm”, “pancreatic mucinous cystic tumour”, “pancreatic mucinous cystic mass”, “pancreatic cyst”, and “pancreatic cystic neoplasm” to identify English language articles describing the diagnosis and treatment of the mucinous cystic neoplasm of the pancreas. In total, 16 322 references ranging from January 1969 to December 2009 were analysed and 77 articles were identified. No articles published before 1996 were selected because MCNs were not previously considered to be a completely autonomous disease. Definition, epidemiology, anatomopathological findings, clinical presentation, preoperative evaluation, treatment and prognosis were reviewed. MCNs are pancreatic mucin-producing cysts with a distinctive ovarian-type stroma localized in the body-tail of the gland and occurring in middle-aged females. The majority of MCNs are slow growing and asymptomatic. The prevalence of invasive carcinoma varies between 6% and 55%. Preoperative diagnosis depends on a combination of clinical features, tumor markers, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound with cyst fluid analysis, and positron emission tomography-CT. Surgery is indicated for all MCNs.

Poorly enhanced areas of pancreatic adenocarcinomas on late-phase dynamic computed tomography: comparison with pathological findings

OBJECTIVES

The aim of the study was to retrospectively compare image findings of poorly enhanced areas (PEAs) of pancreatic adenocarcinomas that show almost no enhancement or obviously hypoattenuating area relative to the surrounding carcinoma on late-phase dynamic computed tomography (CT) with pathological findings.

METHODS

Thirty-nine patients with pancreatic adenocarcinoma underwent dynamic CT and surgery. Poorly enhanced areas were classified according to their size, attenuation value, position, and border on CT imaging and signal intensity on magnetic resonance imaging.

RESULTS

Of the 33 PEAs, 12 showed neoplastic duct-like structure that contained both large tumor gland and dilated pancreatic duct with atypia, 11 showed necrosis, 4 showed retention cyst, 2 showed dilated pancreatic duct without atypia or with limited invasion, 1 showed mucin, and 3 showed no remarkable differences in characteristics compared with surrounding tissue. Neoplastic duct-like structures tended to be well defined (P < 0.01). Necrotic portions tended to show a high attenuation value (P < 0.01) and central position (P < 0.01) and were ill defined (P < 0.01). Retention cysts tended to show a peripheral position (P < 0.01).

CONCLUSIONS

Poorly enhanced areas corresponded to cystic, necrotic, and mucinous components. Image findings demonstrated these characteristics. Necrotic component can be visualized and distinguished with other components and can be a prognostic factor.

Proteases present in some pancreatic cyst fluids may affect mucin immunoassay by degrading antibodies and antigens

OBJECTIVES

Biomarker detection in pancreatic cyst fluids is of importance to improve the diagnosis of mucinous cystadenoma, a precancerous lesion. However, assay protocols are generally established for serum testing.

METHODS

Immunoradiometric assay of gastric M1/MUC5AC mucin was performed on pancreatic cyst fluids with well-characterized monoclonal antibodies.

RESULTS

Among 1466 pancreatic cyst fluids tested, about 10% to 15% of samples presented abnormal behaviors: (i) radioactivity measured after immunoradiometric assay much lower than the blank of the assay and (ii) increasing dilution of the fluids leading to apparent increase of M1/MUC5AC concentration. In contrast, none of the 109 hepatic cyst fluids tested presented interference.We demonstrate that some (n = 54) interfering fluids cause mucin degradation as well as antibody degradation. Western blot analysis showed that the C-terminal part of the M1/MUC5AC apomucin is most sensitive to degradation.

CONCLUSIONS

The presence of proteases that degrade antibodies as well as mucin may explain the pitfalls observed in 3.6% of the samples. To detect this interference, each fluid has to be systematically tested at 1:100 dilution in the presence of a saturating concentration of M1/MUC5AC mucin standard and in the absence of antiprotease reagents. Detection of interference could prevent false results caused by mucin degradation in situ.

Stromal thrombospondin-1 expression is a prognostic indicator and a new marker of invasiveness in intraductal papillary-mucinous neoplasm of the pancreas

The invasion of intraductal papillary-mucinous neoplasm (IPMN) is sometimes difficult to diagnose using only ordinary hematoxylin-eosin sections. The aim of this study was to evaluate the invasion of IPMN more precisely using thrombospondin-1 (TSP1) immunohistochemistry as a useful adjunct to morphological examination. Eighty patients that underwent primary resection for pancreatic IPMNs were retrospectively analyzed. The 80 IPMNs were studied for the expression of TSP1, MUC1-CORE, MUC2, and MUC5AC. The cases were evaluated for dysplasia, the presence of invasion, hisological subtypes, and survival. The 80 IPMNs were classified into 29 intraductal papillary-mucinous adenomas (IPMAs), 10 borderline IPMNs, 18 noninvasive intraductal papillary-mucinous carcinomas (IPMCs), and 23 invasive IPMCs according to the WHO classification. Invasive IPMCs were further divided into 12 minimally invasive IPMCs (MI-IPMCs) and 11 invasive carcinomas originating from IPMCs (IC-IPMCs) according to the Japan Pancreatic Society classification. The rate of strongly positive cases with more than 30% of the cancer stroma area expressing TSP1 was significantly higher in MI-IPMC and IC-IPMC than in noninvasive IPMC (P = 0.035, 0.005). Furthermore, patients in the strongly positive group had a significantly poorer prognosis compared to patients in the negative-weakly positive group (P = 0.008, log-rank test). Of the 80 tumors, 22 were classified into gastric-, 45 into intestinal-, 7 into pancreatobiliary-, and 6 into oncocytic-type IPMNs according to criteria described previously. The cases with a strongly positive expression of TSP1 were frequently detected in the pancreatobiliary and oncocytic types (P = 0.001). In conclusion, stromal TSP1 expression is a prognostic indicator and a new marker of invasiveness in IPMN.

Surgical treatment of cystic neoplasms of the pancreas

CONTEXT: Diagnosis and treatment of cystic neoplasms of the pancreas increased significantly in the last decades. There are only a few Brazilian publications on these tumors. The majority of them are limited to reports of one or few cases. OBJECTIVE: To present our experience with 27 patients with cystic neoplasms of the pancreas. METHODS: Demographic data, clinical manifestations, diagnostic exams, surgical procedures, postoperative complications, and follow-up data of 27 patients with cystic neoplasms of the pancreas were analyzed, according to the histological type of the tumor. RESULTS: There were 10 (37%) serous cystic tumors, 10 (37%) mucinous cystic tumors, 4 (15%) intraductal papillary mucinous tumors, and 3 (11%) solid pseudopapillary tumors or Frantz tumor. All serous cystic tumors, 6 (60%) mucinous tumors, 2 (50%) intraductal papillary mucinous tumors, and 2 (67%) solid pseudopapillary tumors were benign. The age of the patients varied from 31 to 82 years and all tumors were more common in female. Two patients had been treated previously as a pseudocyst. Surgical procedures depended on the location and extension of the tumor. Two patients underwent only laparotomy with tumor biopsy, one cholecystectomy with Roux-en-Y hepaticojejunostomy for jaundice treatment, 6 pancreatoduodenectomy, and 18 partial pancreatectomy. The most common postoperative complication was pancreatic fistula (n = 5; 19%). One patient died of necrotic pancreatitis. Of the 10 patients with serous cystic tumor, only 1 had tumor recurrence at the section border. The three patients with mucinous cystoadenocarcinoma in which was not possible to resect the tumor, died 6 to 24 months after laparotomy. The six patients with benign mucinous tumors did not have tumor recurrence. CONCLUSIONS: The most common cystic neoplasms of the pancreas are serous and mucinous cysts. These tumors are more frequent in female. Although almost all serous cysts are benign, 40% of mucinous cysts are malign. Misdiagnosis may delay appropriate treatment and increase mortality.

Glycosylation variants of mucins and CEACAMs as candidate biomarkers for the diagnosis of pancreatic cystic neoplasms

BACKGROUND AND AIMS

Cystic lesions of the pancreas are increasingly being recognized due to the widespread use of high resolution abdominal imaging. Since certain cyst types are precursors to invasive cancer, this situation presents an opportunity to intervene prior to malignant progression. Effective implementation of that strategy has been hampered by difficulties in clearly distinguishing cystic lesions with no malignant potential from those with malignant potential. Here we explored whether glycosylation variants on specific proteins in cyst fluid samples could serve as biomarkers to aid in this diagnosis.

METHODS

We used a novel antibody-lectin sandwich microarray method to measure the protein expression and glycosylation of mucin (MUC)1, MUC5AC, MUC16, carcinoembryonic antigen, and other proteins implicated in pancreatic neoplasia in cyst fluid samples. Fifty-three cyst fluid samples were obtained from patients with mucinous cystic neoplasms (n=17), intraductal papillary mucinous neoplasms (n=15), serous cystadenomas (n=12), or pseudocysts (n=9), with confirmation of histologic diagnosis at surgical resection.

RESULTS

The detection of a glycan variant on MUC5AC using the lectin wheat-germ agglutinin discriminated mucin-producing cystic tumors (mucinous cystic neoplasms+intraductal papillary mucinous neoplasms) from benign cystic lesions (serous cystadenomas+pseudocysts) with a 78% sensitivity at 80% specificity, and when used in combination with cyst fluid CA 19-9 gave a sensitivity of 87% at 86% specificity. These biomarkers performed better than cyst fluid carcinoembryonic antigen (37%/80% sensitivity/specificity).

CONCLUSIONS

These results demonstrate the value of glycan variants for biomarker discovery and suggest that these biomarkers could greatly enhance the accuracy of differentiating pancreatic cystic tumors. Validation studies will be required to determine the clinical value of these markers.

Pancreatic cystic neoplasms

Cystic neoplasms of the pancreas have been recognized for almost 2 centuries, but the principles of management continue to evolve. Clinicians have a better understanding now of the diverse pathologies and behaviors of cystic neoplasms, and can characterize them more precisely into benign, malignant, and of uncertain potential in their manifestations. Treatment is dependent on accurate diagnosis and tailored to the potential aggressiveness of the lesion, the surgical fitness of the patient, and the probability of effecting long-term palliation or survival of the patient. In this article the authors review the classification based on the World Health Organization classification and the latest evidence-based literature of cystic neoplasms, and present their considerations for surgical management of the various lesions. A better understanding of the biologic potential of cystic neoplasms such as intraductal papillary mucinous neoplasms allows for a more patient-specific evidence-based management plan.

Novel xenograft and cell line derived from an invasive intraductal papillary mucinous neoplasm of the pancreas give new insights into molecular mechanisms

OBJECTIVES

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are a unique entity with malignant potential. Histologically, pancreatic ductal adenocarcinoma (PDAC) arising in IPMN (intraductal papillary mucinous carcinoma [IPMC]) appears similar to sporadic PDAC; biologically, however, IPMC seems to have a less aggressive clinical course. Little is known about the genetic signature of IPMC. In this study, we describe a novel xenograft model and cell culture created to biologically and genetically characterize these tumors.

METHODS

Xenograft mice and cell lines were created from IPMC. Global genomic changes were evaluated by cytogenetic analysis and array comparative genomic hybridization. Specific mutations and sonic hedgehog (Shh) pathway activity were examined and xenografts evaluated for sensitivity to anti-Shh therapy.

RESULTS

Cytogenetic analysis showed a tetraploid karyotype with multiple aberrations. KRAS and p53 mutations and overexpression of the Shh pathway were identified. Array comparative genomic hybridization revealed multiple chromosomal aberrations comparable with previously published data in IPMNs. Murine xenograft tumors were sensitive to anti-Shh treatment.

CONCLUSIONS

Characterization of IPMC cell lines and xenografts reveals similarities to previously published data on IPMN. In comparison to PDAC, moreover, these data reveal shared aberrations and distinct genomic changes. Thus, these xenograft model and cell lines may be useful for future preclinical investigations.

Intraductal oncocytic papillary carcinoma of the pancreas showing numerous hyaline globules in the lumen

Two cases of intraductal oncocytic papillary carcinoma (IOPC) treated surgically were analyzed on light microscopy and immunohistochemistry: that of a 61-year-old man and that of a 55-year-old man. There were no clinical symptoms in either case. Pancreatic abnormalities were discovered incidentally on CT. Various clinical examinations were carried out, and the preoperative diagnosis was intraductal papillary mucinous carcinoma (IPMC) in both cases. Surgery was performed. Macroscopic observation of tissue cross-sections indicated multilocular cystic mass containing polypoid lesions encapsulated by the dilated pancreatic duct. Histologically, the cyst walls were lined by columnar epithelial cells with complex papillary projections associated with oxyphilic cytoplasm, and they were strongly immunoreactive with anti-mitochondrial antibody in the cytoplasm. Electron microscopy showed numerous mitochondria in the cytoplasm. IOPC was diagnosed. Interestingly, amorphous hyaline globules were produced from the oxyphilic cells, which exhibited a bud-like appearance. The hyaline globules were not positive for mucin staining. No case of IPMC with hyaline globules has been reported to date. The production of hyaline globules may be related to oncocytic differentiation. It is suggested that hyaline globules should be regarded as a characteristic of IOPC.

Intraductal oncocytic papillary neoplasms of the pancreas and bile ducts: a description of five new cases and review based on a systematic survey of the literature

BACKGROUND

Intraductal oncocytic papillary neoplasms (IOPN) are rare tumors of the pancreatic and biliary ductal system. It is not absolutely clear if the molecular and clinicopathologic characteristics of IOPN differ significantly from other related lesions, namely intraductal papillary mucinous neoplasms (IPMN). Therefore it is not clear if it is reasonable to consider IOPN as a separate diagnostic and clinical entity.

METHODS

In order to describe the clinicopathologic characteristics of IOPN and to compare them with the IPMN profile, we performed a systematic review of the literature and additionally studied five previously unreported IOPN cases.

RESULTS

IOPN differ from IPMN by lack of K-ras gene mutations in all studied cases. Several differences in the clinical and biological profile between IOPN and IPMN exist, but they are of quantitative rather than of qualitative nature. Additionally, pancreaticobiliary or gastric-foveolar IPMN components may coexist with IOPN component within a single lesion, which suggests at least a partial relation of the pathogenetic pathways of IPMN and IOPN. Importantly, the pathogenesis of accumulation of mitochondria and oxyphilic appearance of IOPN remains unknown.

CONCLUSIONS

At present, there are no reliable criteria other than histopathological picture and K-ras gene status to differentiate IOPN from IPMN. In particular, no clear differences in optimal treatment options and prognosis between these tumors are known. Further studies are needed to clarify the biology of IOPN and to establish their position in clinicopathologic classifications of pancreatic tumors.