Endoscopic ultrasound-guided fine needle aspiration cytology of the pancreas: a morphological and multimodal approach to the diagnosis of solid and cystic mass lesions

Consequences of a Surveillance Strategy for Side-branch Intraductal Pancreatic Mucinous Neoplasms: Long-term Follow-up of One Thousand Cysts

OBJECTIVE

To quantify the rate of progression in surveilled cysts and assess what factors should indicate delayed resection.

BACKGROUND

Side-branch intraductal papillary mucinous neoplasms (SB-IPMNs) are increasingly discovered, making it challenging to identify which patients require resection, thus avoiding inappropriate treatment. Most incidental lesions are surveyed, yet the consequences of that decision remain uncertain.

METHODS

A prospectively maintained database of pancreatic cystic neoplasms was queried for patients with SB-IPMN. Patients with ≥2 imaging studies >6 months apart were included. Clinically relevant progression (CR-progression) was defined by symptoms, worrisome/high-risk stigmata, or invasive cancer (IC). Growth ≥5 mm in 2 years is considered CR-progression; size ≥3 cm alone is not.

RESULTS

Between 1997 and 2023, 1337 patients were diagnosed with SB-IPMN. Thirty-seven (2.7%) underwent up-front surgery; 1000 (75.0%) had >6 months of surveillance.The rate of CR-progression was 15.3% (n = 153) based on size increase (n = 63, 6.3%), main-duct involvement (n = 48, 4.8%), symptoms (n = 8, 5.0%), or other criteria (n = 34, 3.4%). At a median follow-up of 6.6 years (interquartile range: 3.0-10.26), 17 patients (1.7%) developed IC. Those with CR-progression developed IC in 11.1% (n = 17) and high-grade dysplasia (HGD) in 6.5% (n = 10). Nearly half of the cancers were not contiguous with the surveyed SB-IPMN.Size ≥3 cm was not associated with HGD/IC ( P = 0.232). HGD/IC was least common in CR-progression determined by size growth (6.3%) versus main-duct involvement (24%) or other (43%, P < 0.001)Patients with CR-progression demonstrated improved survival (overall survival) with resection on time-to-event ( P < 0.001) and multivariate Cox regression (hazard ratio = 0.205, 0.096-0.439, P < 0.001) analyses. Overall survival was not improved with resection in all patients ( P = 0.244).

CONCLUSIONS

CR-progression for SB-IPMNs is uncommon, with the development of cancer anywhere in the pancreas being rare. Initial size should not drive resection. Long-term and consistent nonoperative surveillance is warranted, with surgery currently reserved for CR-progression, knowing that the majority of these still harbor low-grade pathology.

Grading pancreatic adenocarcinomas on fine needle aspiration cytology. The outstanding issues

OBJECTIVE

The three-tier grading scheme described in "The Papanicolaou Society of Cytopathology (PSC) System for reporting Pancreaticobiliary Cytopathology" (TPSCRPBC) which remained unchanged following the WHO Reporting System for Pancreaticobiliary Cytopathology (WRPBC) was evaluated on pancreatic adenocarcinomas (PACs) reported on endoscopic ultrasound-guided fine needle aspiration cytology (EUS-FNAC).

METHODS

The Papanicolaou and May Grunwald Giemsa-stained smears from 116 cases of PACs were graded using the three-tier grading scheme laid down by TPSCRPBC/WRPBC. Cases exhibiting multiple grades were assigned primary, secondary and tertiary grades. Each case was assigned a grade score, either by adding the primary and secondary grades, by adding the primary and tertiary grades when the tertiary grade was 3 or by doubling the grade when only one grade existed. Necrosis was estimated semi-quantitatively. The inter-observer reproducibility in grading was evaluated using Kappa and Kendall's tau-c. Correlations between the various grades, the stage of the tumour and the amount of necrosis were assessed using Spearman rho and Kendall's tau-b.

RESULTS

31.89% of cases showed one grade, and 68.11% showed at least two grades. 16.38% showed three grades. The two commonest grade scores were 3 and 5. The inter-observer reproducibility for grading and grade scoring was satisfactory. A positive correlation was noted between the grades and the amount of necrosis. No significant correlation was found between the grades, grade scores and the stage of the tumours.

CONCLUSIONS

The TPSCRPBC/WRPBC grading scheme can be suitably applied to PACs with good inter-observer reproducibility. Cases often show multiple grades in the same tumour.

Systematic review of challenging issues in pathology of intraductal papillary mucinous neoplasms

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are a cystic precursor to pancreatic cancer. IPMNs deemed clinically to be at high-risk for malignant progression are frequently treated with surgical resection, and pathological examination of the pancreatectomy specimen is a key component of the clinical care of IPMN patients.

METHODS

Systematic literature reviews were conducted around eight topics of clinical relevance in the examination of pathological specimens in patients undergoing resection of IPMN.

RESULTS

This review provides updated perspectives on morphological subtyping of IPMNs, classification of intraductal oncocytic papillary neoplasms, nomenclature for high-grade dysplasia, assessment of T stage, distinction of carcinoma associated or concomitant with IPMN, role of molecular assessment of IPMN tissue, role of intraoperative assessment by frozen section, and preoperative evaluation of cyst fluid cytology.

CONCLUSIONS

This analysis provides the foundation for data-driven approaches to several challenging issues in the pathology of IPMNs.

Integrating Molecular Analysis into the Pathologic Evaluation of Pancreatic Cysts

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

Cytopathology of solid pancreatic neoplasms: An algorithmic approach to diagnosis

The classification and management of solid pancreatic neoplasms has expanded significantly in recent years because of advances in immunohistochemical markers, molecular diagnostics, and therapeutics. Solid pancreatic masses are subdivided into 1) ill-defined, scirrhous, and stroma-rich (ductal adenocarcinoma) and 2) well circumscribed, cellular, and stroma-poor (including neuroendocrine neoplasms, acinar cell carcinoma, pancreatoblastoma, and solid-pseudopapillary neoplasm). Definitive diagnosis, particularly of stroma-poor, circumscribed tumors, requires the incorporation of radiologic and cytologic findings, along with the judicious use of (broad, but limited) immunohistochemical panels (pancytokeratin and neuroendocrine [synaptophysin], acinar [trypsin], and solid-pseudopapillary neoplasm [β-catenin] markers), along with unstained slides. Depending on the initial results, immunohistochemical panels should be expanded to include more confirmatory (acinar and neuroendocrine) markers. This ensures that adequate material is available for definitive diagnosis/subclassification and, in some cases, grading, and/or molecular studies, particularly of grade 3 neuroendocrine neoplasms and mixed-lineage tumors. The objective of this review is to expand the understanding of the cytomorphology of solid pancreatic neoplasms using an integrated, multidisciplinary approach in their diagnosis. Knowledge and understanding of recent updates in the classification of solid pancreatic neoplasms ensures that cytopathologists appropriately triage specimens, judiciously use and interpret ancillary studies, and incorporate these results in reporting.

Background features in the cytology of pancreatic neoplasms

Cytology is a useful method for diagnosing pancreatic neoplasms. Although endoscopic ultrasound‐guided fine‐needle aspiration has recently become the mainstream method for the diagnosis of pancreatic neoplasms, pancreatic juice and pancreatic duct brushing cytology continue to be useful diagnostic methods for the investigation of pancreatic neoplasms. Diagnoses using pancreatic cytology are primarily based on the features related to tumor cells; however, evaluation of the background features provides important information that could further aid the diagnosis. Pancreatic neoplasms show various histological types, each of which is associated with its own characteristic background features. The necrotic background, desmoplastic stroma, and presence of cancer‐associated fibroblasts are background features of pancreatic ductal adenocarcinoma, a mucinous background is associated with intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, and hyaline globules are observed in solid pseudopapillary neoplasms. However, some background features are associated with more than one histological type of pancreatic neoplasm, highlighting the importance to base a diagnosis on the results of a comprehensive analysis of not only the background features but also the tumor cells. Here, we provide a review of the key background cytological features of pancreatic neoplasms, which can serve as a guide to improve diagnosis and research.

Utility of SOX11 for the diagnosis of solid pseudopapillary neoplasm of the pancreas on cytological preparations

INTRODUCTION

The diagnosis of solid pseudopapillary neoplasm (SPN) on fine needle aspiration specimens can be challenging because of morphological overlap with other pancreatic neoplasms, including pancreatic neuroendocrine tumour (PanNET). SRY-related high-mobility group box 11 (SOX11) is a recently described sensitive and specific marker for SPN diagnosis. However, SOX11 immunocytochemistry on cytological smears has not been reported. We evaluated the utility of SOX11 for diagnosis of SPN on cytological preparations.

METHODS

SOX11 immunocytochemistry was performed on Papanicolaou-stained smears and/or corresponding cell blocks from aspirates of 7 SPN and 10 PanNET cases identified between 2005 and 2020. Findings were compared with those for beta-catenin, a frequently used diagnostic marker for SPN.

RESULTS

Six smears and 6 cell blocks from SPN cases and 8 smears and 10 cell blocks from PanNET cases were available for immunostaining. For SPN, nuclear staining for SOX11 was seen in 6 of 6 (100%) smears and 5 of 6 (83%) cell blocks, with equivocal staining in 1 cell block. In contrast, 7 of 8 (88%) smears and 9 of 10 (90%) cell blocks were negative for SOX11 for PanNet, with equivocal staining seen in 1 case. Beta-catenin immunocytochemistry showed nuclear staining in 6 of 7 (86%) SPN cases and no staining in all 10 (100%) PanNET cases.

CONCLUSIONS

SOX11 detected by immunocytochemistry can serve as a useful diagnostic marker for SPN, in addition to beta catenin, and can be performed on cytological smears in cases without a cell block preparation.

Lymphoid Enhancer Binding Factor 1 (LEF1) and Paired Box Gene 8 (PAX8): A Limited Immunohistochemistry Panel to Distinguish Solid Pseudopapillary Neoplasms and Pancreatic Neuroendocrine Tumors

Solid pseudopapillary neoplasms (SPNs) and pancreatic neuroendocrine tumors (PanNETs) are distinctive entities. However, due to overlapping morphologies, distinguishing them remains a diagnostic challenge. Our study investigates the utility of immunohistochemistry for nuclear lymphoid enhancer binding factor 1 (LEF1) and paired box gene 8 (PAX8) in differentiating these 2 entities. LEF1 and PAX8 immunohistochemistry were performed on fine-needle aspiration cell blocks and surgical resection specimens diagnosed as SPN or PanNET at our institution from January 2007 to August 2016. Eight SPN and 25 PanNET cell blocks and 17 SPN and 34 PanNET surgical resection specimens were examined. On cell blocks, positive staining for LEF1 had high frequency, sensitivity, and specificity for SPN (88%, 88%, and 88%) as did positive staining for PAX8 for PanNET (76%, 76%, and 75%). The findings on surgical resection specimens were consistent with those from cell blocks (LEF1+ in SPN: 100%, 100%, and 97%; PAX8+ in PanNET: 59%, 59%, and 100%). A combined LEF1+/PAX8- phenotype showed high sensitivity and specificity for SPN (cell block: 63% and 100%; surgical specimen: 100% and 98%) as did a LEF1-/PAX8+ phenotype for PanNET (cell block: 64% and 100%; surgical specimen: 59% and 100%). SPN and PanNET exhibit opposite immunophenotypic profiles with LEF1+/PAX8- in SPN and LEF1-/PAX8+ in PanNET. The combination of these 2 stains provides an effective means of distinguishing these 2 entities.

Endoscopic Ultrasound-Guided Fine Needle Aspiration Cytology of Pancreatic Adenocarcinomas Revisited. A Detailed Cytological Analysis

Background

Early detection of pancreatic adenocarcinomas is essential for improving survival. In this regard, endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNAC) has established itself as the method of choice for its ability to target lesions smaller than those which could be targeted by the traditional imaging methods like transabdominal ultrasound. Identifying these tumors correctly on FNA may be challenging because pancreatic adenocarcinomas may show a wide range of morphological features and the presence of contaminants from the gastrointestinal tract may show up as potential pitfalls. This study presents detailed cytomorphological analyses of 59 cases reported as pancreatic adenocarcinomas on smears and cell blocks. The clinical and histopathology follow-up data wherever available have also been presented.

Materials and Methods

EUS-FNAC smears and cell blocks from cases reported as pancreatic adenocarcinomas were retrospectively evaluated with individual assessments of a range of features related to cellularity, cellular arrangement, cytoplasmic qualities, and nuclear features. Aspirates from peripancreatic lymph nodes, histopathology sections, and clinical records were reviewed wherever available.

Results

Nonneoplastic cells like pancreatic ductal cells and acinar cells, duodenal, and gastric epithelia were detected along with neoplastic cells showing a wide range of variations in different cytomorphological characters. Often, a mixture of features was noted in the same case. Cell block preparations served as useful adjuncts since they made it possible to render unequivocal diagnoses of malignancies in cases where smears were hypocellular.

Conclusion

The study creates a useful knowledge base of cytomorphological features of pancreatic adenocarcinomas.

Practical Applications of Molecular Testing in the Cytologic Diagnosis of Pancreatic Cysts

Mucinous pancreatic cysts are precursor lesions of ductal adenocarcinoma. Discoveries of the molecular alterations detectable in pancreatic cyst fluid (PCF) that help to define a mucinous cyst and its risk for malignancy have led to more routine molecular testing in the preoperative evaluation of these cysts. The differential diagnosis of pancreatic cysts is broad and ranges from non-neoplastic to premalignant to malignant cysts. Not all pancreatic cysts—including mucinous cysts—require surgical intervention, and it is the preoperative evaluation with imaging and PCF analysis that determines patient management. PCF analysis includes biochemical and molecular analysis, both of which are ancillary studies that add significant value to the final cytological diagnosis. While testing PCF for carcinoembryonic antigen (CEA) is a very specific test for a mucinous etiology, many mucinous cysts do not have an elevated CEA. In these cases, detection of a KRAS and/or GNAS mutation is highly specific for a mucinous etiology, with GNAS mutations supporting an intraductal papillary mucinous neoplasm. Late mutations in the progression to malignancy such as those found in TP53, p16/CDKN2A, and/or SMAD4 support a high-risk lesion. This review highlights PCF triage and analysis of pancreatic cysts for optimal cytological diagnosis.

Management Algorithms for Pancreatic Cystic Neoplasms: The Surgeon's Perspective

CONTEXT.—

The detection of pancreatic cystic neoplasms (PCNs) has increased owing to the advancement and widespread use of imaging modalities, resulting in differences between past and current management methods for PCNs, including intraductal papillary mucinous neoplasms (IPMNs). Therefore, clinicians should accurately diagnose and determine appropriate treatment strategies. However, previously published treatment guidelines for IPMNs present different indications for treatment.

OBJECTIVE.—

To review the current status of PCNs, including epidemiologic change, malignancy risk, and factors for treatment, and to provide the optimal management algorithms for PCNs, including IPMNs, from the clinician's point of view.

DATA SOURCES.—

Literature review of published studies and the authors' own work.

CONCLUSIONS.—

The treatment of PCNs relies on the type of cyst that is present or suspected. Serous cystic neoplasms are usually benign, and observation is sufficient. However, surgical treatment is required for mucinous cystic neoplasms, and malignancy risk differs according to lesion size. Solid pseudopapillary neoplasms also require surgery. The detection of small IPMNs has been increasing, and most branch duct-type IPMNs are dormant. However, cysts 3 cm or larger or growing branch duct-type IPMNs must be carefully monitored because of the increasing risk of malignancy. Therefore, surveillance strategies should be different according to the size of the lesions. A tailored approach is needed for selecting surgery or surveillance, considering the malignancy potential of the lesion and patient-associated factors such as operative risks and life expectancy. Nomograms are valuable tools for selecting treatment methods as a customized approach for IPMNs.

Confocal endomicroscopy for evaluation of pancreatic cystic lesions: a systematic review and international Delphi consensus report

Background and study aims  The aim of thi systematic review and consensus report is to standardize the practice of endoscopic ultrasound (EUS-guided needle-based confocal laser endomicroscopy (nCLE) for pancreatic cystic lesion (PCL) evaluation. Methods  We performed an international, systematic, evidence-based review of the applications, outcomes, procedural processes, indications, training, and credentialing of EUS-nCLE in management of PCLs. Based on available clinical evidence, preliminary nCLE consensus statements (nCLE-CS) were developed by an international panel of 15 experts in pancreatic diseases. These statements were then voted and edited by using a modified Delphi approach. An a priori threshold of 80 % agreement was used to establish consensus for each statement. Results  Sixteen nCLE-CS were discussed. Thirteen (81 %) nCLE-CS reached consensus addressing indications (non-communication PCL meeting criteria for EUS-FNA or with prior non-diagnostic EUS-FNA), diagnostic outcomes (improved accuracy for mucinous PCLs and serous cystadenomas with substantial interobserver agreement of image patterns), low incidence of adverse events (fluorescein-associated and pancreatitis), procedural processes (nCLE duration, manipulation of needle with probe), and training (physician knowledge and competence). Conclusion  Based on a high level of agreement pertaining to expert consensus statements, this report standardizes the practice of EUS-nCLE. EUS-nCLE should be systematically considered when EUS-FNA is indicated for PCL evaluation.

The applicability of Papanicolaou Society of Cytopathology system on reporting endoscopic ultrasound-guided fine needle aspiration cytology specimens of pancreatic lesions in situations with limited availability of ancillary tests. Experience at a single laboratory

INTRODUCTION

The Papanicolaou Society of Cytopathology (PSC) system of reporting pancreatobiliary cytology is a standardised reporting nomenclature that uses a six-tiered scheme of diagnostic categories utilising routine microscopy and ancillary tests such as biochemical and molecular analysis of cyst fluids and immunochemistry. The objective of this study was to determine the applicability of the PSC system on endoscopic ultrasound-guided fine needle aspiration cytology samples reported at the cytopathology laboratory, Mubarak Al Kabeer Hospital, in Kuwait with special emphasis on situations with limited availability of ancillary tests.

METHODS

In total, 132 cases of endoscopic ultrasound-guided fine needle aspiration cytology samples from pancreatic lesions were categorised according to PSC system guidelines after examining the glass slides and reviewing the clinical, imaging and ancillary test findings. These review diagnoses were compared with the diagnoses rendered during initial reporting. Correlation with histopathology reports was done wherever available.

RESULTS

In 23 (17.42%) of 132 cases, re-categorisation was necessary between initial and reviewed diagnoses. In 16 cases, re-categorisations were because of non-analogous categories between initial and reviewed diagnosis. In the remaining seven, they were due to identification of newer cytomorphological and imaging findings or because of issues arising from unavailability of sufficient material for ancillary investigations.

CONCLUSION

All cases could be categorised using the PSC system with a moderate number of re-categorisations between initial and reviewed diagnoses. In certain circumstances, limited availability of ancillary tests, resulted in non-diagnostic categories whereas in other such circumstances, diagnostic categories could be assigned with certain conceptual modifications to the PSC guidelines.

Mesenchymal neoplasms of the tubular gut and adjacent structures: experience with EUS-guided fine-needle aspiration cytopathology

INTRODUCTION

Unlike epithelial malignancies, mesenchymal neoplasms arising within the tubular gut are less often encountered in endoscopic ultrasound-guided (EUS) fine-needle aspiration biopsies (FNABs). Nonetheless, preoperative diagnosis of such neoplasms has important therapeutic and prognostic value. We report our experience with this category of neoplasms from the past decade.

MATERIALS AND METHODS

We performed a 10-year retrospective search at our respective institutions to identify EUS-guided FNAB cases of mesenchymal neoplasms arising from the tubular gut wall and closely adjacent structures. Cytopathologic diagnoses were compared to corresponding surgical pathology (SP) when available. Cases with either no confirmatory cell block (CB) immunohistochemical (IHC) staining, or no SP were excluded.

RESULTS

Two-hundred eighty-two cases (M:F = 1:1; age range: 25-94 years, mean age = 60 years) of EUS-guided FNAB from the tubular gut met our criteria. Onsite adequacy was performed on nearly all cases. Case numbers: 209 gastrointestinal stromal tumors (GIST), 58 smooth muscle neoplasms, and 15 miscellaneous neoplasms. Of these, 188 (67%) had SP follow-up. We found that 258 (91%) aspirates had a correct specific diagnosis, 3 (1%) were nondiagnostic, 18 (6%) had indeterminate diagnoses, and 3 (1%) had incorrect diagnoses (2 leiomyosarcomas mistaken as leiomyoma, and 1 fibrosclerotic lesion mistaken as inflammatory pseudotumor). Of 94 cases with no SP, all had a specific cytologic diagnosis based on confirmatory IHC staining from the CB including 61 GISTs, 29 smooth muscle neoplasms, and 4 miscellaneous tumors.

CONCLUSION

This study endorses the clinical utility of EUS-guided FNAB in the diagnosis of tubular gut mesenchymal neoplasms. A definitive and accurate diagnosis is possible in over 90% of cases, chiefly when cytomorphology is coupled with optimal cellularity and IHC from a concurrent CB. EUS-guided FNAB diagnosis of mesenchymal tubular gut neoplasms may play an important role in determining neoadjuvant therapy as targeted therapy evolves.

Similarities and differences in guidelines for the management of pancreatic cysts

Accurate diagnosis of Pancreatic cysts (PC) is key in the management. The knowledge of indications for surgery, the role of endoscopic ultrasound-guided fine needle aspiration, cyst fluid analysis, imaging, and surveillance of PC are all important in the diagnosis and management of PC. Currently, there are many guidelines for the management of PC. The optimal use of these guidelines with a patient-centered approach helps diagnose early cancer and prevent the spread of cancer.

Stratifying Intraductal Papillary Mucinous Neoplasms by Cyst Fluid Analysis: Present and Future

A significant proportion of patients with intraductal papillary mucinous neoplasms (IPMNs) undergo surgical resection in order to prevent or treat pancreatic cancer at the risk of significant perioperative morbidity. Efforts have been made to stratify the potential risk of malignancy based on the clinical and radiographic features of IPMN to delineate which cysts warrant resection versus observation. An analysis of the cyst fluid obtained by preoperative endoscopic examination appears to be correlative of cyst type and risk, whereas serum markers and radiographic findings have not yet reached a level of sensitivity or specificity that proves they are clinically meaningful. In this review, we investigate the current cyst fluid analysis studies and present those that have shown promise in effectively stratifying high-risk versus low-risk lesions. While new cyst fluid markers continue to be identified, additional efforts in testing panels and marker composites in conjunction with clinical algorithms have also shown promise in distinguishing dysplasia and the risk of malignancy. These should be tested prospectively in order to determine their role in guiding the surveillance of low-risk lesions and to evaluate the new markers detected by proteomics and genetic sequencing.

Role of Ancillary Testing on Endoscopic US-Guided Fine Needle Aspiration Samples from Cystic Pancreatic Neoplasms

Pancreatic cysts are increasingly detected on imaging studies. Accurate determination of the cyst type is important to provide appropriate care for the patients. It is also very clear that not one single modality can provide adequate diagnostic information. A multidisciplinary approach is the key to the diagnosis of pancreatic cysts. In this setting, the role of ancillary testing, which includes biochemical testing (carcinoembryonic antigen and amylase levels in the cyst), molecular testing (e.g., KRAS, GNAS, VHL, and CTNB1), and/or immunohistochemical tests are very important to obtain an accurate diagnosis. This review will discuss helpful ancillary tests in common pancreatic cyst neoplasms and how to approach the diagnosis of pancreatic cysts.

Moray micro forceps biopsy improves the diagnosis of specific pancreatic cysts

BACKGROUND

Making a specific diagnosis of pancreatic cysts preoperatively is difficult. The new disposable Moray micro forceps biopsy (MFB) device allows tissue sampling from the pancreatic cyst wall/septum and aims to improve diagnosis. This study compares the diagnostic performance of the MFB with the current conventional analysis of pancreatic cyst fluid (PCF).

METHODS

A total of 48 patients sampled with MFB were identified. Cysts were classified as mucinous on PCF based on extracellular mucin/mucinous epithelium, carcinoembryonic antigen (CEA) levels ≥192 ng/mL, or KRAS/GNAS mutation. A diagnosis of intraductal papillary mucinous neoplasm was supported by GNAS mutation; a diagnosis of serous cystadenoma was supported by Von Hippel-Lindau tumor suppressor (VHL) mutation. A diagnosis of mucinous cystic neoplasm required the presence of subepithelial ovarian-type stroma. A high-risk cyst was defined as a mucinous cyst with high-grade dysplasia or an adenocarcinoma. Comparisons in diagnostic performance between PCF and MFB were made.

RESULTS

The mean age of the patients was 69.6 years (range, 27-90 years); 25 of 48 patients (52.1%) were female. Cysts were in the pancreatic head (13 patients), neck (2 patients), body (20 patients), and tail (13 patients), averaging 3.1 cm (range, 1.2-6.0 cm). There was concordance with mucinous versus nonmucinous classification (60.4% for PCF vs 58.3% for MFB; P = .949). Three high-risk cysts were detected by PCF and 2 were detected by MFB (P = .670). However, MFB diagnosed significantly more specific cysts compared with PCF (50.0% for MFB vs 18.8% for PCF; P<.001).

CONCLUSIONS

PCF analysis and MFB have comparable performance in distinguishing between mucinous and nonmucinous cysts and for detecting high-risk cysts. However, MFB was found to be superior for diagnosing specific cyst subtypes, thus adding significant value to preoperative patient management. Cancer Cytopathol 2018;126:414-20. © 2018 American Cancer Society.

Effect of Reprimo Down-regulation on Malignant Transformation of Intraductal Papillary Mucinous Neoplasm

OBJECTIVES

Reprimo gene is a cytoplasmic protein belonging to a family of molecules controlled by p53 that inhibits cell cycle progression. Ectopic expression of Reprimo results in cell cycle arrest at the G2 phase. The aim of this study was to investigate the impact of Reprimo expression on tumorigenesis of intraductal papillary mucinous neoplasm (IPMN).

METHODS

Thirty-seven surgical cases of IPMN were collected retrospectively. Twenty-eight patients had benign IPMNs (low-grade dysplasia, n = 18; intermediate-grade dysplasia, n = 10), and the remaining 9 had malignant IPMNs (high-grade dysplasia, n = 4; invasive carcinoma, n = 5). DNA from tumor samples was extracted. DNA methylation patterns of Reprimo were determined by the methods of methylation-specific polymerase chain reaction and immunohistochemistry. The methylation status of Reprimo was compared between benign IPMNs and malignant IPMNs.

RESULTS

The incidence of aberrant DNA methylation of Reprimo was significantly higher in malignant IPMNs than in benign IPMNs (78% vs 32%, P = 0.016). Furthermore, the incidence of immunohistochemical Reprimo expression was significantly lower in malignant IPMNs than in benign IPMNs (22% vs 82%, P = 0.002).

CONCLUSIONS

Reprimo methylation was found more frequently in malignant IPMNs. Reprimo methylation is involved in malignant transformation of IPMNs.

Immunocytochemistry for SOX-11 and TFE3 as diagnostic markers for solid pseudopapillary neoplasms of the pancreas in FNA biopsies

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare malignant tumors that can be sampled via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Although diagnosing SPNs can be straightforward in cases with a classic morphology and a typical immunoprofile, challenges can occur with morphologic variants or limited specimens. Recently, 2 immunohistochemical stains, SRY-related high-mobility group box 11 (SOX-11) and transcription factor E3 (TFE3), have been demonstrated to be highly sensitive and specific for SPNs in pancreatic resection specimens. The current study evaluates the diagnostic utility of these stains with EUS-FNA.

METHODS

Thirteen EUS-FNA specimens from SPNs with sufficient material for immunocytochemistry were identified from 2000 to 2016. These cases were compared with 13 EUS-FNA specimens of non-SPN pancreatic neoplasms. Immunocytochemistry for SOX-11, TFE3, and β-catenin was performed on all cell blocks and then was scored independently by 2 pathologists in a masked manner.

RESULTS

Nuclear reactivity for SOX-11 was detected in 13 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in sensitivity and specificity values of 100%, a positive predictive value (PPV) of 1, and a negative predictive value (NPV) of 1. Nuclear reactivity for TFE3 was detected in 9 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in a sensitivity of 69.2%, a specificity of 100%, a PPV of 1, and an NPV of 0.765. Nuclear reactivity for β-catenin was detected in 13 of 13 SPNs and in 1 of 13 non-SPNs; this resulted in a sensitivity of 100%, a specificity of 92.3%, a PPV of 0.929, and an NPV of 1.

CONCLUSIONS

SOX-11 is a sensitive and specific immunocytochemical stain for SPNs in EUS-FNA specimens, and it may be useful as a diagnostic marker for distinguishing SPNs from its cytologic mimics. Cancer Cytopathol 2017;125:831-7. © 2017 American Cancer Society.

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

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

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

Preoperative characteristics and cytological features of 136 histologically confirmed pancreatic mucinous cystic neoplasms

BACKGROUND

Mucinous cystic neoplasms (MCNs) of the pancreas present a management conundrum. The majority are benign but all are resected due to their malignant potential. Recent studies have recommended nonsurgical management. In the current study, the authors analyzed the preoperative imaging, cytology, and cyst fluid characteristics of 136 histologically confirmed MCNs to assess predictors of a high-risk (HR) cyst for surgical triage.

METHODS

MCNs resected at the Massachusetts General Hospital between 1990 and 2014 formed the study cohort. Patient demographics, cyst size, and mural nodules (MNs) by endoscopic ultrasound, cytology, and cyst fluid carcinoembryonic antigen and amylase levels were correlated with histological grade. A HR cyst was defined as high-grade dysplasia or invasive carcinoma on histology. Performance characteristics were assessed for each parameter, with a cyst size ≥3 cm or a MN on imaging and malignant cytology considered to be "true-positive" results for predicting malignancy.

RESULTS

Only 15 of the 136 cysts had HR histology (11%). On average, patients with HR cysts were older than those with low-risk cysts (55 years vs 49 years, respectively). High-grade cytology was the most accurate predictor of malignancy (95%) followed by MN and cyst size together (88%) and MN alone (83%). The average carcinoembryonic antigen level (in ng/mL) increased with the grade of dysplasia but the ranges overlapped between low risk and HR cysts.

CONCLUSIONS

To the authors' knowledge, the current study is the largest series to date analyzing the cytological features of histologically confirmed MCN. Cytology is insensitive but very specific for detecting a HR MCN and outperformed imaging for the detection of HR MCN. Endoscopic ultrasound-guided fine-needle aspiration and cytology should be performed on any clinically suspected MCN that is being considered for conservative management. Cancer Cytopathol 2017;125:169-177. © 2016 American Cancer Society.

Endoscopic ultrasound-guided fine needle aspiration cytology of metastatic renal cell carcinoma to the pancreas: A multi-center experience

Introduction:

The increasing use of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytology to examine pancreatic neoplasms has led to an increase in the diagnosis of metastases to the pancreas. Renal cell carcinoma (RCC) is the most common metastasis to the pancreas. Our study examines 33 cases of metastatic RCC to the pancreas sampled by EUS-FNA from four large tertiary care hospitals.

Materials and Methods:

We searched the cytopathology database for RCC metastatic to the pancreas diagnosed by EUS-FNA from January 2005 to January 2015. Patient age, history of RCC, nephrectomy history, follow-up postnephrectomy, radiological impression, and EUS-FNA cytologic diagnosis were reviewed.

Results:

Thirty-three patients were identified. The average age was 67.5 years (range, 49–84 years). Thirty-two patients had a previous documented history of RCC. One patient had the diagnosis of pancreatic metastasis at the same time of the kidney biopsy. Thirty-one patients had been treated with nephrectomy. Twenty-seven patients were being monitored annually by computed tomography or magnetic resonance imaging. Twenty-five patients had multiple masses by imaging, but 8 patients had a single mass in the pancreas at the time of EUS-FNA. EUS-FNA of 20 cases showed classic morphology of RCC. Thirteen cases had either “atypical” clinical-radiologic features or morphologic overlaps with primary pancreatic neoplasms or other neoplasms. Cell blocks were made on all 13 cases and immunochemical stains confirmed the diagnosis.

Conclusions:

EUS-FNA cytology is useful for the diagnosis of metastatic RCC to the pancreas. Cytomorphology can be aided with patient history, imaging analyses, cell blocks, and immunochemical stains.

Pancreatic Ductal Adenocarcinoma and Its Variants

Pancreatic cancer represents the seventh leading cause of cancer death in the world, responsible for more than 300,000 deaths per year. The most common tumor type among pancreatic cancers is pancreatic ductal adenocarcinoma, an infiltrating neoplasm with glandular differentiation that is derived from pancreatic ductal tree. Here we present and discuss the most important macroscopic, microscopic, and immunohistochemical characteristics of this tumor, highlighting its key diagnostic features. Furthermore, we present the classic features of the most common variants of pancreatic ductal adenocarcinoma. Last, we summarize the prognostic landscape of this highly malignant tumor and its variants.

Endoscopic ultrasound-guided fine needle aspiration biopsy of pancreatic lesions. An 8-year analysis of single institution material focusing on efficacy and learning progress

OBJECTIVE

To evaluate the efficacy and the learning curve of the endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNAB) diagnostics of pancreatic lesions over 8 years (2007-2014).

MATERIAL AND METHODS

EUS-FNAB using a Linear Echoendoscope Olympus was performed in 531 patients, mostly without rapid on-site evaluation (ROSE). Smears plus cytoblock sections were used routinely. Immunocytochemistry was utilised as indicated.

RESULTS

The average, satisfactory sampling rate increased from the 61.2% in the first 3-year period to 72.9% in the last 3-year period (P = 0.008). The availability of the material for cytoblocks increased from 36.4% in the first period to 75.3% in the last period (P = 0.017). The efficacy of cytoblocks increased from 39.6% to 46.2% (P = 0.086). Comparing the first and last 3-year periods, the indication for immunocytochemistry did not rise substantially (5.2% and 8.5% respectively), but the predictive value of immunocytochemistry rose from 56.3% to 100.0% (P = 0.001). The most frequent diagnostic result was malignancy confirmation - both primary (41.2%) and metastatic (2.1%). In cases with representative samples and follow-up information, the specificity, sensitivity, positive predictive value and accuracy were high from the beginning. The negative predictive value decreased slightly in the last 3-year period.

CONCLUSION

The pancreatic EUS-FNAB without ROSE represents a suboptimal arrangement conditioned with our staff/time/location reality. Nevertheless, within the last 3 years of our activity, nearly three-quarters of patients profit from the diagnostic contribution of this procedure.

Diagnostic utility of arborizing stromal meshwork fragments in mucinous tumors

INTRODUCTION

Arborizing stromal meshwork fragments (ASMFs) have been proposed as a useful clue to differentiate mucin associated with mucinous adenocarcinoma from contaminating mucus during endobronchial ultrasound-guided transbronchial needle aspiration. Our aim was to retrospectively review cytology cases with mucinous material to determine the utility of ASMFs in diagnosing mucinous tumors.

MATERIAL AND METHODS

Diff-Quik stained smears from archival cytology cases (N = 40) were reviewed, including adenocarcinomas with mucinous features, cystic mucinous neoplasms, and control cases with mucin contamination. Specimens were procured by image-guided fine needle aspiration (FNA) (16 cases), endoscopic ultrasound-guided FNA (22 cases), pathologist-performed FNA (1 case), and fluid drainage (1 case). All cases were reviewed for ASMFs, which were defined as metachromatic, spidery extensions with frayed edges within a background of mucinous material.

RESULTS

ASMFs were identified in 4 (10% of cases, 14% of adenocarcinomas) cases of metastatic gastrointestinal mucinous adenocarcinomas in various locations (liver, lymph node, lung, and bone), but absent in mucin contamination. ASMFs in Diff-Quik stained smears were magenta-colored and corresponded to intervening stroma between dissecting mucin in the tumor. Nonarborizing desmoplastic stroma, inspissated mucus, cartilage fragments, transgressing vessels in renal cell carcinoma, and mucus-like material in pancreatic pseudocysts can morphologically mimic ASMFs.

CONCLUSION

These data show that ASMFs may be encountered in some (14%) cases of adenocarcinoma with mucinous differentiation. When present, ASMFs can be diagnostically helpful to differentiate adenocarcinoma with mucinous features from contaminating mucus, if reliably distinguished from mimics. Diagn. Cytopathol. 2016;44:805-810. © 2016 Wiley Periodicals, Inc.

Endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic cysts by combined cytopathology and cystic content analysis

Recent advances in imaging technology have resulted in an increase in incidental discoveries of pancreatic cystic lesions. Pancreatic cysts comprise a wide variety of lesions and include non-neoplastic cysts and neoplastic cysts. Because some pancreatic cysts have more of a malignant potential than others, it is absolutely essential that an accurate diagnosis is rendered so that effective care can be given to each patient. In many centers, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has emerged as the modality of choice that enables one to distinguish between mucinous and non-mucinous lesion, diagnose malignancy and collect cyst fluid for further diagnostic studies, such as pancreatic enzyme levels, molecular analysis and other tumor biomarkers. The current review will focus on EUS-guided FNA and the cytological diagnosis for pancreatic cysts.

Endoscopic ultrasound-guided fine-needle aspiration cytology in pancreaticobiliary carcinomas: diagnostic efficacy of cell-block immunocytochemistry

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration cytology was demonstrated to be a useful tool for the diagnosis and staging of pancreaticobiliary neoplastic lesions. Nonetheless, the diagnostic value of this procedure may be limited by low cellularity of the specimen, contamination of intestinal cells and unfeasibility of ancillary immunocytochemical procedures. The present study was to evaluate its usefulness in the diagnosis of neoplastic lesions.

METHODS

A series of 46 pancreaticobiliary carcinomas with available cell block preparations was submitted to immunocytochemistry against cytokeratins, carcinoembryonic antigen, E-cadherin, CD10 and p53. The sensitivity, specificity, positive and negative predictive values of the cytological smear in the discrimination of malignant lesions were calculated and compared with those of cell block preparation with the immunocytochemical stains against p53 and CD10.

RESULTS

According to our findings, the use of cell block preparations together with immunostains against p53 and CD10 allowed to discriminate malignant versus benign specimens with higher sensitivity than the only cytological examination. In detail, CD10 immunostaining was of significant help for the discrimination between cytological contaminants, such as benign gastrointestinal cells, and the neoplastic elements of pancreaticobiliary well differentiated adenocarcinomas. Also, intense nuclear immunoreactivity for p53 was encountered in about 2/3 of the cases and identified pancreatic malignancy with high sensitivity.

CONCLUSIONS

We suggest that immunocytochemistry against both CD10 and p53 could be applied case by case, mainly to differentiate gastrointestinal and pancreatic benign cellular contaminants showing hyperplasia or reactive changes from differentiated pancreaticobiliary adenocarcinomas.

Endoscopic ultrasonography-guided fine-needle aspiration cytology of surgically confirmed cystic pancreatic neuroendocrine tumors: a Mayo Clinic experience

INTRODUCTION

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) cytology is widely used to evaluate solid and cystic pancreatic lesions preoperatively. Pancreatic neuroendocrine tumors (PanNETs) are typically solid, but when they are cystic, differentiation from other pancreatic cystic neoplasms can be challenging. We examined cases of cystic PanNETs (cPanNETs) from 3 Mayo Clinic Hospitals focusing on the EUS-FNA cytology.

MATERIALS AND METHODS

A total of 21 EUS-FNA cases of cPanNETs with histology confirmation were identified from the Mayo Clinic Health System database. The patients' demographic data, clinical, radiological, and EUS characteristics were obtained. EUS-FNA cytology and surgical pathology were reviewed.

RESULTS

Among the 21 patients with cPanNETs, only 2 of 21 cases had suggestion of cPanNET on preoperative imaging (computed tomography/magnetic resonance imaging). On EUS, most cPanNETs (16/ of 21) had ≥1 high-risk stigmata or worrisome feature per the Sendai Consensus guidelines. None of the cases had an elevated carcinoembryonic antigen level. EUS-FNA cytology was positive or suspicious for cPanNET in 15 of 21 cases (71.4%). Immunohistochemical stains of neuroendocrine markers were performed on all the positive or suspicious cases and showed positivity for ≥1 neuroendocrine marker. All cases had surgical resection and the diagnosis of cPanNET was confirmed on each case.

CONCLUSIONS

Although computed tomography/magnetic resonance imaging has a low specificity for detecting cPanNETs, high-risk features on EUS and low carcinoembryonic antigen levels should raise the suspicion for cPanNET. EUS-FNA cytology along with immunohistochemical stains has a high accuracy in establishing the preoperative diagnosis of cPanNET.

Cyst fluid amylase and CEA levels in the differential diagnosis of pancreatic cysts: a single-center experience with histologically proven cysts

OBJECTIVE

Cyst fluid amylase is a potential marker for pseudocysts and intraductal papillary mucinous neoplasms (IPMN). This study aimed to evaluate the diagnostic role of cyst fluid amylase and to determine the optimal cutoff values of cyst fluid amylase and carcinoembryonic antigen (CEA) for the differential diagnosis of pancreatic cysts.

METHODS

Based on the pancreatic cyst database at Massachusetts General Hospital, a total of 78 patients with histologically proven cysts [pancreatic pseudocyst (PP), n = 16; mucinous cystic neoplasm, mucinous cystic neoplasm (MCN), n = 22; IPMN, n = 40] were selected. Complete cyst fluid amylase and CEA values were analyzed.

RESULTS

Thirty two of 78 patients were male with median age of 60.4 years (range, 24-84). Cyst diameter ranged from 5 to 130 mm. For cyst fluid amylase, there was significant difference between PP and MCN (median, 30,034.50 vs. 4,723.50 U/L; p < 0.05) or IPMN (30,034.50 vs. 1,585.00; p = 0.001), but no difference between MCN and IPMN. For cyst fluid CEA, there was a significant difference between PP and MCN (median, 26.00 vs. 627.50 ng/mL; p < 0.001) or IPMN (26.00 vs. 356.50; p < 0.001). Median amylase and CEA values were significantly different between PP and mucinous neoplasms (MCN/IPMN) (p < 0.01 and p < 0.001). Optimal cutoff values of 6,800 U/mL for amylase and 50 ng/mL for CEA correlated with the crossover of the sensitivity and specificity curves for differentiating PP and mucinous neoplasms. The overall accuracies of cyst fluid amylase and CEA were 69 and 85%, respectively.

CONCLUSIONS

Cyst fluid amylase analysis does not differentiate between MCN and IPMN. The combination of cyst fluid CEA and amylase value may increase the diagnostic accuracy for differentiating mucinous neoplasms from pseudocysts.

Endoscopic ultrasound-guided pancreatic fine-needle aspiration: potential pitfalls in one institution's experience of 1212 procedures

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has emerged as the diagnostic modality of choice for mass lesions in the pancreas. The objective of the current study was to determine the accuracy and pitfalls of EUS-FNA in the diagnosis of pancreatic lesions in cases that involved follow-up surgical resection.

METHODS

Cases of EUS-FNA of pancreatic lesions performed from 2007 to mid-2012 for which subsequent surgical resection was performed were retrieved from the department's database. The accuracy of the cytologic diagnosis was assessed using the histological diagnosis as the gold standard. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated. "Neoplastic," "suspicious," and "malignant" were classified as a positive cytologic diagnosis. In one calculation method, "atypical" was also included as a positive cytologic diagnosis whereas in another it was not considered to be a positive cytological result. The cases with a cytologic-histological discrepancy were reviewed to identify sources of errors.

RESULTS

A total of 1212 cases from 1104 patients (518 women and 586 men; age range, 18-94 years [average age, 63.5 years]) were identified. Cytologic diagnoses included 52 unsatisfactory, 224 benign, 129 atypical, 140 neoplasm, 35 suspicious, and 632 malignant diagnoses. Of these cases, 397 patients had histological follow-up information available. The sensitivity, specificity, positive predictive value, and negative predictive value were 83.2%, 85.9%, 95.9%, and 56.1%, respectively, with atypical cases excluded from the analysis. When atypical cases were included as a positive cytologic diagnosis, the sensitivity, specificity, positive predictive value, and negative predictive value were 86.7%, 67.9%, 90.7%, and 58.5%, respectively, and were 73.7%, 87.7%, 95.6%, and 48.0%, respectively, when atypical cases were included as a negative cytologic diagnosis. The major difficulty in EUS-FNA cytology was to differentiate pancreatic mucinous neoplasms from contaminants of gastric mucosa. Other pitfalls included differentiating mucinous neoplasm from extensive pancreatic intraepithelial neoplasia, and endocrine tumor from nesidioblastosis versus acinar cell carcinoma or intrapancreatic spleen.

CONCLUSIONS

EUS-FNA is a valuable tool for the diagnosis of pancreatic lesions, especially solid malignant tumors. Cytologic-radiological correlation is essential in differentiating pancreatic mucinous neoplasms from gastric mucosa, because the former usually are found to have characteristic features on imaging. Pathologists should be aware of the pitfalls in the cytologic diagnosis of pancreatic lesions that may significantly change the clinical management of the patients.

Preoperative GNAS and KRAS testing in the diagnosis of pancreatic mucinous cysts

PURPOSE

Management guidelines for pancreatic intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms (MCN) are based on the assumption that mucinous cysts can be accurately distinguished from other pancreatic cystic lesions. Previous studies using surgical material have identified recurrent mutations in GNAS and KRAS in pancreatic mucinous neoplasms. Yet, the diagnostic utility of testing for both genes in pancreatic cyst fluid obtained by endoscopic ultrasound-fine-needle aspiration (EUS-FNA) remains unclear.

EXPERIMENTAL DESIGN

GNAS and KRAS testing was performed on EUS-FNA pancreatic cyst fluid from 91 pancreatic cysts: 41 IPMNs, 9 IPMNs with adenocarcinoma, 16 MCNs, 10 cystic pancreatic neuroendocrine tumors (PanNET), 9 serous cystadenomas (SCA), 3 retention cysts, 2 pseudocysts, and 1 lymphoepithelial cyst.

RESULTS

Mutations in GNAS were detected in 16 (39%) IPMNs and 2 (22%) IPMNs with adenocarcinoma. KRAS mutations were identified in 28 (68%) IPMNs, 7 (78%) IPMNs with adenocarcinoma, and 1 (6%) MCN. Mutations in either gene were present in 34 (83%) IPMNs, 8 (89%) IPMNs with adenocarcinoma, and 1 (6%) MCN. No mutations were found in cystic PanNETs, SCAs, retention cysts, pseudocysts, and a lymphoepithelial cyst. GNAS and KRAS mutations had 100% specificity [95% confidence interval (CI), 0.83-1.00] but 65% sensitivity (95% CI, 0.52-0.76) for mucinous differentiation. Among IPMNs, mutations in either gene had 98% specificity (95% CI, 0.86-1.00) and 84% sensitivity (95% CI, 0.70-0.92).

CONCLUSIONS

The combination of GNAS and KRAS testing was highly specific and sensitive for IPMNs; however, the lack of sensitivity for MCNs highlights the need for additional markers to improve the detection of pancreatic mucinous neoplasms.

Standardized terminology and nomenclature for pancreatobiliary cytology: The Papanicolaou Society of Cytopathology Guidelines

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreatobiliary cytology including indications for endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) biopsy, techniques of EUS-FNA, terminology and nomenclature of pancreatobiliary disease, ancillary testing and post-biopsy treatment and management. All documents are based on the expertise of the authors, a review of the literature, discussion of the draft document at several national and international meetings over an 18 month period and synthesis of online comments of the draft document on the Papanicolaou Society of Cytopathology web site [www.papsociety.org]. This document selectively presents the results of these discussions and focuses on a proposed standardized terminology scheme for pancreatobiliary specimens that correlate cytological diagnosis with biological behavior and increasingly conservative patient management of surveillance only. The proposed terminology scheme recommends a six-tiered system: Non-diagnostic, negative, atypical, neoplastic [benign or other], suspicious and positive. Unique to this scheme is the “neoplastic” category separated into “benign” (serous cystadenoma) or “other” (premalignant mucinous cysts, neuroendocrine tumors and solid-pseudopapillary neoplasms (SPNs)). The positive or malignant category is reserved for high-grade, aggressive malignancies including ductal adenocarcinoma, acinar cell carcinoma, poorly differentiated neuroendocrine carcinomas, pancreatoblastoma, lymphoma and metastases. Interpretation categories do not have to be used. Some pathology laboratory information systems require an interpretation category, which places the cytological diagnosis into a general category. This proposed scheme provides terminology that standardizes the category of the various diseases of the pancreas, some of which are difficult to diagnose specifically by cytology. In addition, this terminology scheme attempts to provide maximum flexibility for patient management, which has become increasingly conservative for some neoplasms.

Cytologic features of pancreatic adenocarcinoma with "vacuolated cell pattern." report of a case diagnosed by endoscopic ultrasound-guided fine-needle aspiration

The "vacuolated cell pattern" has only been recently described as a distinct morphologic variant of pancreatobiliary adenocarcinoma. Herein, we report the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) cytologic features of a case of pancreatic adenocarcinoma with "vacuolated cell pattern" occurring in a 60-year-old man. The aspirate smears and cell block sections from the EUS-FNA of a 23.5 mm hypoechoic pancreatic head mass were highly cellular, showing variably-sized crowded three-dimensional cell clusters, flat sheets, and numerous highly atypical single cells. The background was bloody and showed necrotic debris, but no discernible mucus. The most striking feature of the aspirate was the presence of numerous very large (20-50 µm) vacuoles, occupying the entire cytoplasm, pushing the nuclei to the side and indenting them, that imparted a cribriform appearance to the sheets of neoplastic cells. The non-vacuolated neoplastic cells were large, had abundant dense (squamoid) cytoplasm, irregularly contoured hyperchromatic nuclei, and prominent macronucleoli. Histologic evaluation of the pancreatectomy specimen showed a "vacuolated cell pattern" adenocarcinoma composed of poorly formed glands, solid sheets, and infiltrating single cells with pleomorphic nuclei and large cytoplasmic vacuoles. To our knowledge, this is the first report describing the cytologic features of this rather uncommon morphologic variant of pancreatic adenocarcinoma. Recognition of this morphologic variant of pancreatic adenocarcinoma in ESU-FNA samples allows its differentiation from primary and metastatic signet-ring cell carcinomas.

Cystic pancreatic neuroendocrine tumors: the value of cytology in preoperative diagnosis

BACKGROUND

Cystic pancreatic neuroendocrine tumors (cPanNETs) account for 13% to 17% of PanNETs. Although the value of endoscopic ultrasound (EUS) imaging and cyst fluid analysis (CFA) in their preoperative diagnosis has been well described, limited information is available about the diagnostic role of cytology samples obtained from fine-needle aspiration (FNA).

METHODS

Cytopathology records between 1992 and 2013 were searched for all reports of cysts interpreted as PanNET. Patient demographics, clinical and radiologic information, CFA, histopathology, and cytopathology findings were recorded. Performance characteristics of cytology and EUS for the accurate diagnosis of cPanNET were calculated.

RESULTS

In total, 35 FNAs from 33 patients with cPanNETs were identified, and 34 EUS were performed. Cytology made a specific diagnosis of a cPanNET in 71% of the biopsies compared with a specific diagnosis by EUS in 38% of cases. An interpretation of suspicious for cPanNET was given in 77% of cases by cytology and in 47% by EUS. Cytology identified 86% of the lesions as high-risk pancreatic cysts compared with 56% by EUS. Diagnostic morphology was present on both cytology and cell block preparations in 60% of aspirates, on cytology only in 20%, and on cell block only in 20%. CFA was performed on 51% cyst fluids. All cysts but 1 revealed low carcinoembryonic antigen levels (range, 0.2 to >500 ng/mL; mean, 29.5 ng/mL), and amylase levels were <500 U/L in all but 2 cases (range, 16-1493 U/L; mean, 205 U/L).

CONCLUSIONS

Cytology is the most accurate test for preoperative diagnosis of cPanNETs. EUS is insufficiently accurate for independent diagnosis, and carcinoembryonic antigen and amylase analyses are noncontributory.

Ancillary Studies, Including Immunohistochemistry and Molecular Studies, in Pancreatic Cytology

Fine-needle aspiration biopsy of the pancreas is indicated for sampling of solid and cystic masses. Preoperative cytologic diagnosis of pancreatic ductal adenocarcinoma and cystic lesions on cytology can be problematic, and ancillary studies may help confirm diagnosis. Ancillary studies in pancreatic cytology include special stains, immunohistochemistry, mutational analyses of specific genes, cyst fluid analysis of tumor markers and enzymes, and, in some instances, flow cytometry. Proteomics, microRNA sequencing, and whole-exome gene sequencing have been used to illustrate the progression of pancreatic neoplasms and identify key diagnostic markers. This article summarizes recent literature on ancillary studies in pancreatic fine-needle aspiration samples.

Standardized terminology and nomenclature for pancreatobiliary cytology: the Papanicolaou Society of Cytopathology guidelines

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreatobiliary cytology including indications for endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) biopsy, techniques of EUS-FNA, terminology and nomenclature of pancreatobiliary disease, ancillary testing, and postbiopsy treatment and management. All documents are based on the expertise of the authors, a review of the literature, discussions of the draft document at several national and international meetings over an 18-month period and synthesis of online comments of the draft document on the Papanicolaou Society of Cytopathology web site (www.papsociety.org). This document selectively presents the results of these discussions and focuses on a proposed standardized terminology scheme for pancreatobiliary specimens that correlate cytological diagnosis with biological behavior and increasingly conservative patient management of surveillance only. The proposed terminology scheme recommends a six-tiered system: Nondiagnostic, Negative, Atypical, Neoplastic (benign or other), Suspicious and Positive. Unique to this scheme is the "Neoplastic" category separated into "benign" (serous cystadenoma), or "Other" (premalignant mucinous cysts, neuroendocrine tumors, and solid-pseudopapillary neoplasms). The positive or malignant category is reserved for high-grade, aggressive malignancies including ductal adenocarcinoma, acinar cell carcinoma, poorly differentiated neuroendocrine carcinomas, pancreatoblastoma, lymphoma, and metastases. Interpretation categories do not have to be used. Some pathology laboratory information systems require an interpretation category, which places the cytological diagnosis into a general category. This proposed scheme provides terminology that standardizes the category of the various diseases of the pancreas, some of which are difficult to diagnose specifically by cytology. In addition, this terminology scheme attempts to provide maximum flexibility for patient management, which has become increasingly conservative for some neoplasms.

Secondary tumors of the pancreas diagnosed by endoscopic ultrasound-guided fine-needle aspiration: a 10-year experience

Determining whether a pancreatic mass is a primary or secondary neoplasm is necessary for appropriate treatment. We reviewed our experience using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for diagnosis of pancreatic tumors to identify clinical and cytopathologic characteristics of metastatic disease. We reviewed all cases of tumors metastatic to the pancreas evaluated at The University of Texas MD Anderson Cancer Center and The Methodist Hospital in Houston, Texas during the period from 2002 to 2012. The review included cytologic specimens, clinical history, radiologic findings, primary tumor type, and clinical follow-up. We identified 66 patients with disease metastatic to the pancreas for which cytologic material was available: 38 (58%) men and 28 (42%) women, with an average age of 63 years (range, 40-89 years). Most metastases (98%) were single lesions, and nearly half were located in the head of the pancreas (30/66). The most common site of origin for these metastases was kidney (27 [41%] cases). Follow-up information was available for 65 (98%) patients, and duration of follow-up ranged from <1 to 10 years (mean, 2.3 years). Thirty-three patients (50%) were alive at the time of the most recent follow-up contact. Of the 25 patients with metastatic renal cell carcinoma, clear cell type, 19 (76%) were alive at the time of the most recent follow-up. It was concluded that metastases may mimic primary pancreatic carcinomas both clinically and cytologically. Ancillary studies in conjunction with clinical history are necessary for the accurate diagnosis of FNAs of secondary pancreatic tumors.

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.

Cercariform cells: another cytologic feature distinguishing solid pseudopapillary neoplasms from pancreatic endocrine neoplasms and acinar cell carcinomas in endoscopic ultrasound-guided fine-needle aspirates

BACKGROUND

Solid pseudopapillary neoplasm (SPPN) is a rare tumor of unknown origin that occurs predominantly in the body or tail of the pancreas in young women. The authors recently identified cercariform (Greek: tailed) cells, similar to those described in urothelial carcinomas, as a consistent cytologic feature in ultrasound-guided fine-needle aspiration (EUS-FNA) samples from SPPNs. The objective of the current multi-institutional study was to define the value of these cells in the differential diagnosis of SPPN with other neoplasms characterized cytologically by the presence of monotonous, uniform cells in pancreatic aspirates: pancreatic neuroendocrine tumors (Pan-NETs) and acinar cell carcinomas (ACCs).

METHODS

The files of 4 academic hospitals were searched for SPPNs, Pan-NETs, and ACCs that were diagnosed by EUS-FNA. The slides were reviewed, and several cytologic features were recorded semiquantitatively to identify discriminating features between SPPNs, Pan-NETs, and ACCs.

RESULTS

From the analysis of 18 SPPNs, 4 ACCs, and 20 Pan-NETs, the following cytologic features were identified as common to all 3 neoplasms: single cells and rosettes/acinar cell groups, round-to-plasmacytoid cells, pale-to-granular cytoplasm, fine vacuoles, and binucleated cells. Papillary structures, cercariform cells, large cytoplasmic vacuoles, reniform nuclei, hyaline globules/magenta-colored material, and degenerative features (cholesterol crystals, calcifications, foam cells, or giant cells) were significantly more common in SPPNs. Prominent nuclear grooves were encountered in only 4 of 18 SPPNs.

CONCLUSIONS

The current results indicated that the presence of cercariform cells is another useful clue for the cytologic diagnosis of SPPN in challenging cases.

Optimizing the multimodal approach to pancreatic cyst fluid diagnosis: developing a volume-based triage protocol

BACKGROUND

The objective of this study was to develop a triage algorithm to optimize diagnostic yield from cytology, carcinoembryonic antigen (CEA), and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) testing on different components of a single pancreatic cyst fluid specimen. The authors also sought to determine whether cell block supernatant was suitable for CEA and KRAS testing.

METHODS

Fifty-four pancreatic cysts were triaged according to a volume-dependent protocol to generate fluid (neat and supernatant) and cell block specimens for cytology, comparative CEA, and KRAS testing. Follow-up histology, diagnostic cytology, or a combined clinicopathologic interpretation was recorded as the final diagnosis.

RESULTS

There were 26 mucinous cystic lesions and 28 nonmucinous cystic lesions with volumes ranging from 0.3 mL to 55 mL. Testing different components of the specimens (cell block, neat, and/or supernatant) enabled all laboratory investigations to be performed on 50 of 54 cyst fluids (92.6%). Interpretive concordance was observed in 17 of 17 cases (100%) and in 35 of 40 cases (87.5%) that had multiple components tested for CEA and KRAS mutations, respectively. An elevated CEA level (>192 ng/mL) was the most sensitive test for the detection of a mucinous cystic lesion (62.5%) versus KRAS mutation (56%) and "positive" cytology (61.5%). KRAS mutations were identified in 2 of 25 mucinous cystic lesions (8%) in which cytology and CEA levels were not contributory.

CONCLUSIONS

A volume-based protocol using different components of the specimen was able to optimize diagnostic yield in pancreatic cyst fluids. KRAS mutation testing increased diagnostic yield when combined with cytology and CEA analysis. The current results demonstrated that supernatant is comparable to neat fluid and cell block material for CEA and KRAS testing.