Pitfalls in endoscopic ultrasound-guided fine-needle aspiration and how to avoid them

Liquid-based cytology features of pancreatic acinar cell carcinoma: comparison with other non-ductal neoplasms of the pancreas

BACKGROUND

Acinar cell carcinoma (ACC) is a rare malignant epithelial neoplasm, which shares many cytomorphological features with other non-ductal pancreatic neoplasms such as pancreatic neuroendocrine neoplasm (PanNEN) and solid-pseudopapillary neoplasm (SPN). Due to the relative rarity of these tumors, pathologists are less familiar with the cytological features, especially on liquid-based cytology (LBC) which has been relatively recently introduced for endoscopic ultrasound-guided fine needle aspiration specimens.

METHODS

We evaluated the detailed cytological features of 15 histologically confirmed ACC (7 conventional smears [CS], 8 LBC), and compared them with the LBC features of SPN (n = 9) and PanNEN (n = 9).

RESULTS

Compared with CS, LBCs of ACC demonstrated significantly less bloody background. All ACCs demonstrated prominent nucleoli and macronucleoli on LBC. On comparison with the LBC features of SPN and PanNEN, most ACCs demonstrated a necrotic background with apoptotic debris while PanNEN and SPN did not show these features. Acinar structures were predominantly observed in ACC, while frequent pseudopapillary structures were seen only in SPN. Prominent nucleoli and macronucleoli were only seen in ACC.

CONCLUSIONS

ACC had characteristic cytological features that could be observed on LBC preparations, such as high cellularity, necrotic/apoptotic background, nuclear tangles, acinar arrangement of cells, and macronucleoli. These findings also help distinguish ACC from PanNEN and SPN on LBC. It is important to be familiar with these features, as an accurate diagnosis on endoscopic ultrasound-guided fine needle aspiration cytology would have impact on the management of the patient.

A Unique Approach to Obtaining Tissue in a Difficult to Access Indeterminate Biliary Stricture: Percutaneous Cholangioscopy and Biopsy

When evaluating biliary strictures, establishing a diagnosis can present challenges. The first-line approach of endoscopic retrograde cholangiopancreatography can often involve anatomic restrictions. Traditionally, percutaneous transhepatic cholangioscopy has been the answer for biopsies unable to be obtained with the modalities above but requires time for large tract dilation and days of sinus tract maturation to allow for a scope. We present a novel case of percutaneous digital cholangioscopy with SpyGlass DS, a small caliber scope traditionally used with endoscopic retrograde cholangiopancreatography, used for percutaneous transhepatic cholangioscopy after previous failed attempts by several different standard methods. Our case highlights a multidisciplinary approach in ultimately diagnosing malignancy.

Bcl-10, trypsin and synaptophysin helps recognize acinar cell and mixed acinar neuroendocrine cell carcinoma of the pancreas on both preoperative cytological samples and needle biopsy specimens

OBJECTIVE

Acinar cell carcinoma (ACC) of the pancreas are known to be rare and difficult to be recognize because they mimic other unrelated tumors (neuroendocrine, solid pseudopapillary) with different clinical behavior. Especially in the setting of inoperable patients, fine needle aspiration cytology (FNAC), core needle biopsy (FNAB) and immunocyto/histochemistry (ICC/IHC) play a crucial role in the differential diagnosis. The biological material available for ICC tests obtained by minimal invasive procedures is usually limited. Aim of the current study was to evaluate diagnostic panel based on a limited number of ICC markers for typing preoperatively ACC of the pancreas.

METHODS

Of 1820 needle sampling procedures performed and related to pancreatic lesions, 21 cases were extracted with a confirmed diagnosis of ACC on histology. Of them,12 were pure ACC and 9 mixed acinar-neuroendocrine carcinoma (MANEC). Smears of ACC, MANEC and a control group composed of 34neuroendocrine, 7solid pseudopapillary, 50ductal and 4 adenosquamous carcinoma were assessed with an ICC panel made up of BCL10, trypsin, synaptophysin, chromograninA, β-catenin.

RESULTS

On cytology, BCL10 sensitivity and specificity for ACC was 100%. Trypsin correctly recognized 90% of the cases. Synaptophysin was helpful to correctly identify all the cases with a mixed neuroendocrine component. No significant cross-reaction was observed between BCL10 and trypsin in any of the control group case.

CONCLUSIONS

BCL10 is a determinant marker for the diagnosis of acinar cell carcinoma and mixed acinar neuroendocrine cell carcinoma of the pancreas in a pre-operative citologic/histologic setting.

EUS-guided FNA in Diagnosing Pancreatic Lesions: Strength and Cytological Spectrum

Introduction:

Early and accurate diagnosis is paramount for improving the therapeutic efficacy of pancreatic cancers. Endoscopic ultrasonography–fine needle aspiration (EUS-FNA) cytology has come up with the advantage of an early and accurate diagnosis of pancreatic cancers. This study was conducted to analyze the spectrum of pancreatic lesions cytology, and appraise the diagnostic accuracy of EUS-FNA cytology for pancreatic solid and cystic lesions.

Materials and Methods:

This retrospective study includes 288 EUS-guided pancreatic FNA cases. Clinical data, laboratory tests, cytopathology, histopathology, and imaging reports were retrieved. The final diagnosis was based on EUS-FNA cell block and/or pathology in surgical specimens, with immunohistochemistry support. The results of EUS-guided FNA were compared with the final diagnoses to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results:

Among 288 EUS-guided pancreatic FNA cases, 175 (62.0%) were malignant. The mean age was 57.8 ± 13.5 years and 50.1 ± 13.7 years, and the mean size of the lesion was 4.1 ± 1.8 cm and 2.2 ± 1.1 cm in malignant and benign groups, respectively. Sensitivity, specificity, PPV, and NPV of EUS-FNA cytology for solid malignant lesions were 98.3%, 95.1%, 98.3%, and 95.1%, and those for cystic lesions were 88%, 92.3%, 100%, and 100%. Diagnostic accuracy of EUS-FNA cytology for solid and cystic pancreatic lesions is 97.4% and 95.0%, respectively. In conclusion of the above; diagnosis of pancreatic solid and cystic malignancy can be assigned from a composite of the EUS-FNA cytology, cell block preparation and immunohistochemistry Diagnosis of pancreatic solid and cystic malignancy can be assigned from a composite of the EUS-FNA cytology, cell block preparation, and immunohistochemistry.

Clinical features, onsite evaluation, and follow-up results in patients with suspicious for adenocarcinoma on EUS-guided FNA of pancreas

BACKGROUND

Occasionally, an interpretation of suspicious for adenocarcinoma is made for endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) of pancreas. In this study, we aimed to assess onsite evaluation and follow-up results for FNAs with suspicious for adenocarcinoma (FNA-SUS) in order to identify likely factors that are associated with this interpretation.

DESIGN

A total of 53 pancreatic FNA-SUS cases and 149 pancreatic FNAs with an interpretation of adenocarcinoma (FNA-ADC) were included in current study. Clinical characteristics, onsite evaluation results, and follow-up results were collected and analyzed.

RESULTS

Compared with FNA-ADC category, FNA-SUS category was associated with increased cystic/ill-defined lesions on imaging, increased frequency of inadequate materials (onsite evaluation), increased total smear/slide number, and increased number of cases with limited materials on permanent slides/sections. For follow-up resections, 21% of FNA-SUS cases (7 of 34) showed benign, dysplastic changes or neuroendocrine tumors and 79% (27 of 34) showed adenocarcinoma with increased frequency of well-differentiated type. In contrast, all FNA-ADC cases showed adenocarcinoma. The average age of those 7 FNA-SUS cases with non-adenocarcinoma on follow-up was significantly younger than that of 27 cases with adenocarcinoma. FNA-SUS cases with adenocarcinoma on follow-up showed even greater frequency of inadequate materials during onsite evaluation and more increased total smear slide number than FNA-ADC cases.

CONCLUSION

Our data demonstrated several clinicopathologic factors that are likely associated with a suspicious cytology. In younger patients with suspicious cytology and non-mass forming lesion, surgical management should be taken with caution as a considerable percentage of patients showed only benign or low-grade dysplastic changes.

Endoscopic ultrasound guided fine-needle aspiration: What variables influence diagnostic yield?

BACKGROUND

Endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) plays an important role in the diagnosis of various lesions. We sought to determine factors that influence the diagnostic yield of EUS-FNA, specifically, the presence of a cytopathologist, FNA site, and the endoscopist's skill.

METHODS

The data on cytopathologist's availability, duration of procedure, number of passes made, and diagnostic material for cell block (CB) preparation was collected over an 18 months period.

RESULTS

230 specimens (218 patients) were obtained from pancreas (114), lymph node (64), submucosal lesions of the gastrointestinal tract (27), liver (8), and miscellaneous (17) sites. The results were classified as informative (77.8%) and non-informative (NI) (22.2%). The NI rate was significantly high, when a cytopathologist was absent (P = .0008). As the likelihood of cytopathologist's presence increased from 35.8% to 82.9%, the CB quality increased (P < .0001). In the absence of a cytopathologist, the likelihood of NI result increased more than 2-fold (P = .03) and of an inadequate CB increased 3-fold (P < .0001). The more experienced endoscopist "C" (compared to the less experienced "A + B") was less likely to get inadequate material (40.5% vs. 66.3%) (P = .0001).

CONCLUSION

The diagnostic yield of EUS-FNA is significantly related to the presence of an on-site cytopathologist and endoscopist's skill in procuring diagnostic material.

Cytologic criteria to reduce error in EUS-FNA of solid pseudopapillary neoplasms of the pancreas

INTRODUCTION

Standardization of error classification in pathology remains an important issue. This study assesses the extent of error in cytopathologic diagnosis of solid pseudopapillary neoplasms (SPN) of the pancreas. Because of morphologic overlap of SPN and pancreatic neuroendocrine neoplasms (NET), we compared cytologic characteristics to determine which best distinguishes these entities.

MATERIALS AND METHODS

We collected cases diagnosed as SPN either by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) by cytology or surgical pathology from January 2000 to March 2013. An equal number of NET cases were randomly selected. Cytology and surgical pathology cases were evaluated for diagnostic errors and patient impact. Cytologic features in SPN and NET were scored based on presence of previously described characteristics.

RESULTS

A total of 17 patients with EUS-FNA were diagnosed with SPN by cytology or surgical pathology. Of those, 14 had surgical follow-up and 13 had adequate cell blocks and immunohistochemistry. There were 5 discrepancies between cytology and surgical pathology (5 of 14, 36%). There were no false positives or false negatives, but 5 misclassifications: 4 diagnosed as NET on cytology, and 1 as NET versus SPN. All misclassification errors were associated with no harm. When compared with NET, fine chromatin, nuclear grooves, pseud papillae, pink stroma, and hyaline globules are statistically significantly associated with SPN.

CONCLUSIONS

EUS-FNA of pancreatic SPN has excellent positive and negative predictive value, with no false positives or false negatives in this 12-year study. Only misclassification errors as pancreatic NET were made with minimal impact. We suggest that the presence of 3 of 5 major cytologic criteria offer accuracy in diagnosing SPN to prevent misclassification.

Efforts to improve the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration for pancreatic tumors

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is widely used to obtain a definitive diagnosis of pancreatic tumors. Good results have been reported for its diagnostic accuracy, with high sensitivity and specificity of around 90%; however, technological developments and adaptations to improve it still further are currently underway. The endosonographic technique can be improved when several tips and tricks useful to overcome challenges of EUS-FNA are known. This review provides various techniques and equipment for improvement in the diagnostic accuracy in EUS-FNA.

Pitfalls in EUS FNA

Although endoscopic ultrasound (EUS) fine-needle aspiration (FNA) is a safe and accurate procedure, the diagnostic yield varies. Factors contributing to the diagnostic accuracy of EUS FNA include endosonographer and cytopathologist experience, EUS image recognition, accurate FNA targeting of the lesion, proper specimen collection and handling, use of ancillary techniques, and accurate cytologic interpretation. Errors in performance or judgment made before, during, or after the procedure may affect the results of the EUS FNA. The authors discuss the potential pitfalls of EUS FNA and methods to avoid their occurrence to optimize the diagnostic yield, efficiency, and safety of the procedure.

Clear cell variant of solid pseudopapillary neoplasm of pancreas diagnosed by fine needle aspiration: A case report and review of the literature

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare tumor of uncertain malignant potential, predominantly affecting young adult females. We report a case of clear cell variant of SPN, which was diagnosed by fine needle aspiration biopsy. The aspirate was highly cellular and exhibited delicate branching papillary structures with central capillaries covered with several layers of plasmacytoid tumor cells. Acinar and rosette-like formations, as well as single neoplastic cells were also observed. An unusual cytologic feature was the presence of large, clear cytoplasmic vacuoles. The diagnosis of SPN was confirmed by characteristic immunocytochemical staining pattern including nuclear staining for β-catenin, cytoplasmic staining for vimentin and lack of reactivity for cytokeratin.

Intraductal tubulopapillary neoplasm with expansile invasive carcinoma of the pancreas diagnosed by endoscopic ultrasonography-guided fine needle aspiration: a case report

Intraductal tubulopapillary neoplasm (ITPN) of the pancreas, a novel entity included in the World Health Organization 2010 classification, accounts for <1% of all pancreatic exocrine neoplasms and the number of reported cases is limited in the English literature. Herein we describe the cytologic features of ITPN with invasive carcinoma showing expansile growth on endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) cytology. A 74-year-old male patient is presented with a 6.2 cm irregular mass in the head of the pancreas. Microscopic examination of EUS-FNA material showed abundant branching clusters of cells, with some scattered discohesive cells. High power magnification revealed tubular and cribriform patterns with central lumina, containing mucinous or proteinaceous secretions. The constituent cells were relatively uniform and showed mild to intermediate nuclear atypia. Intracytoplasmic mucin was not identified. On cell-block preparation, luminal spaces of clusters contained wispy luminal mucin. Immunohistochemically, constituent cells were positive for MUC1 and MUC6, and were negative for MUC5AC. The large cribriform and tubular clusters with luminal spaces containing wispy mucin were considered to be diagnostic clues for the cytologic diagnosis of ITPN by EUS-FNA. MUC1, MUC6, and MUC5AC immunohistochemistry for cell-block preparation appears to be a useful adjunctive tool to confirm the diagnosis. On EUS-FNA, ITPN should be included in the differential diagnosis of a pancreatic mass lesion showing good circumscription.

Diagnostic error assessment and associated harm of endoscopic ultrasound-guided fine-needle aspiration of neuroendocrine neoplasms of the pancreas

BACKGROUND

Over the past decade, the standardization of error classification in anatomic pathology has become an important issue. The objective of the current study was to assess the extent of errors occurring in the cytopathologic diagnosis of neuroendocrine lesions of the pancreas, and to classify these errors and their associated harm.

METHODS

Information on all cases diagnosed as a neuroendocrine neoplasm either by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in cytology or by surgical pathology between 2000 and 2012 was collected. Using standardized error and harm classification, the authors reviewed the cytology and surgical pathology material and evaluated the type and the cause of diagnostic errors and their impact on the patient.

RESULTS

A total of 177 patients who underwent EUS-FNA were diagnosed with a neuroendocrine neoplasm either by cytology or surgical pathology. Eighty of these cases had surgical follow-up available at the study institution. Of these 80 cases, 56 had an adequate cell block and immunohistochemistry was performed. There were 14 discrepancies noted between cytologic and surgical pathologic diagnoses. There were 9 false-negative cases, consisting of 3 interpretation errors and 6 cytology sampling errors. There were 5 misclassifications, including 4 cases of solid pseudopapillary neoplasm and 1 case of neuroendocrine carcinoma (diagnosed as adenocarcinoma on cytology). There were no surgical pathology errors noted. All errors were associated with no or minor harm.

CONCLUSIONS

EUS-FNA of pancreatic neuroendocrine neoplasms has excellent diagnostic performance, with no false-positive diagnoses reported. When an adequate sample is obtained, the most significant error is misclassification, which is most often associated with solid pseudopapillary neoplasm. The harm associated with diagnostic errors is at most minor.

Errors and mistakes in the ultrasound diagnosis of the pancreas

The differential diagnosis of the focal lesions in the region of the pancreas is difficult due to the similarity of clinical and radiological pictures of neoplastic and non-neoplastic lesions. This paper presents the most common causes of errors in ultrasound diagnosis of pancreatic pathologies. Attention was paid to the errors resulting from the structural variants of the pancreas and those caused by the neighborhood of intestine, stomach and other organs or vessels. Moreover, the article presents mistakes in the interpretation of ultrasound images of normal pancreas as well as its inflammatory and neoplastic lesions. The errors and mistakes in question were divided into three categories: 1) mistakes related to the anatomical structure of the pancreas (anatomical variants, echostructure and echogenicity, course of the splenic artery); 2) mistakes related to anatomical structures localized in the vicinity of the pancreas (caudate lobe of the liver, other organs and intestinal loops surrounding the head of the pancreas, vessels and bile ducts, lymph nodes in the region of the pancreas or duodenal diverticula and tumors); 3) mistakes related to the pathologies of the pancreas (inflammatory and neoplastic lesions including differentiation between inflammatory tumors and malignant masses). In spite of the progress of imaging techniques, the differential diagnosis of focal solid lesions remains the prime problem of imaging examinations of the pancreas. The major aim of the ultrasound examination is early detection of pancreatic neoplasm. Improper performance of the examination or a failure to perform a repeated scan when the conditions for the assessment of the pancreas are not favorable or, what is worse, description of normal pancreas when it is not clearly and entirely visible, constitute errors.

Fine-needle aspiration features of paraduodenal pancreatitis (groove pancreatitis): a report of three cases

Chronic pancreatitis is notorious for mimicking both the clinical and radiologic presentation of pancreatic carcinoma. Paraduodenal pancreatitis is believed to result from focal chronic pancreatitis which affects the minor papilla of the duodenum. Currently, there is limited information available regarding the cytologic features of paraduodenal pancreatitis. In this study, we report the cytologic features of three patients with paraduodenal pancreatitis who had EUS-guided FNAs of the pancreas. The cytologic features were highly variable between cases, likely due to sampling of the various components of paraduodenal pancreatitis. The most common findings were spindled stromal cells, foamy cells, and granular debris. Although most often interpreted as negative for malignancy, the sampling of an area with abundant spindle cells or Brunner gland hyperplasia can mimic neoplasia. Careful attention to the clinical history and radiologic description can help to prevent over-diagnosis on FNA.

Cytomorphologic and immunophenotypical features of acinar cell neoplasms of the pancreas

BACKGROUND

Acinar cell neoplasms of the pancreas are rare but when encountered, the diagnosis is often established based on cytology specimens. Diagnostic accuracy is important because acinar cell carcinomas are aggressive yet may mimic tumors with different outcomes and management.

METHODS

The authors identified all patients with a diagnosis of acinar cell neoplasm in the institutional database; assessed cytomorphology and immunocytochemistry for trypsin, chymotrypsin, synaptophysin, chromogranin A, and MIB-1; and compared all cytology and final histological diagnoses for diagnostic discrepancies.

RESULTS

Cytological features were described for 16 histologically proven malignant acinar cell neoplasms: acinar cell carcinoma (8 cases), mixed acinar-neuroendocrine carcinoma (6 cases), mixed acinar-ductal carcinoma (1 case), and pancreatoblastoma (1 case).The majority of aspirates from acinar cell cystadenomas were nondiagnostic or negative (5 of 6 cases; 83%). Acinar and neuroendocrine differentiation that was detected by immunocytochemistry in >20% of tumor cells was found to be correlated with mixed acinar-neuroendocrine carcinoma histology. Cytohistological correlation included 32 patients with 17 discordant diagnoses (53%). The following preoperative cytology diagnoses proved to be acinar cell neoplasms on resection: neuroendocrine tumor (5 cases), adenocarcinoma (5 cases), atypical ductal cells (2 cases), solid pseudopapillary neoplasm, and hepatocellular carcinoma. Three aspirates diagnosed as acinar cell carcinoma by cytology proved to be chronic pancreatitis (2 cases) and ductal adenocarcinoma (1 case).

CONCLUSIONS

Acinar cell carcinoma has a distinctive cytological appearance but is frequently misdiagnosed on cytology. Immunocytochemistry is useful for identifying acinar differentiation.

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.

Commercial molecular panels are of limited utility in the classification of pancreatic cystic lesions

The PathfinderTG biomarker panel is useful in the evaluation of pancreatic cysts that have clinical features suspicious for malignancy, but its utility in classifying fine-needle aspiration biopsies from small pancreatic cystic lesions is yet to be proven. We used morphology to classify 20 pancreatic cyst cytology aspirates, all of which met radiographic criteria for close observation. Cases were cytologically classified as consistent with pseudocyst, serous cystadenoma, or mucinous neoplasm with low-grade, intermediate-grade, or high-grade dysplasia and analyzed for carcinoembryonic antigen. Redpath Integrated Pathology Inc. rendered diagnoses of nonmucinous (reactive/indolent or serous) or mucinous (low-risk or at risk) cyst on the basis of results of the PathfinderTG panel (KRAS mutations, DNA content, and loss of heterozygosity at microsatellites linked to tumor suppressor genes). Cytologic and commercial laboratory diagnoses were concordant in only 7 (35%) cases. Seven cysts classified as mucinous with low-grade dysplasia by cytology were interpreted as nonmucinous on the basis of the PathfinderTG panel, 2 of which were resected mucinous cysts. Two pancreatitis-related pseudocysts were misdiagnosed as low-risk mucinous cysts; 1 mucinous cyst with low-grade dysplasia was considered at risk for neoplastic progression using the PathfinderTG panel. Only 1 cyst misclassified as pseudocyst by cytology, but low-risk mucinous cyst by molecular analysis, proved to be a mucinous cystic neoplasm with low-grade dysplasia after surgical resection. We conclude that the PathfinderTG panel may aid the classification of pancreatic lesions, but is often inaccurate and should not replace cytologic evaluation of these lesions.

Targeting tyrosine kinases in cancer: the converging roles of cytopathology and molecular pathology in the era of genomic medicine

Because of knowledge gained in the field of cancer biology, clinicians are currently witnessing an explosion of molecular tests as companion diagnostics to targeted therapies against growth factor receptors and their signaling pathways. Such tests are being applied increasingly to cytology specimens as essential components of genomic medicine, because less invasive diagnostic procedures are becoming the norm. The objective of this review was to present an overview of the current and future role of cytopathology in molecular diagnostics, including the adequacy of cytology specimens for such studies. The authors also discuss the critical methodologic aspects of the molecular assays used for the selection of tyrosine kinase treatment for oncology patients.

Endoscopic-ultrasound-guided fine-needle aspiration and the role of the cytopathologist in solid pancreatic lesion diagnosis

Endoscopic ultrasound (EUS) is the most sensitive imaging modality for solid pancreatic lesions. The specificity, however, is low (about 75%). It can be increased to 100% with an accuracy of 95% by the addition of fine-needle aspiration (FNA). Cytopathology plays an important role. The final diagnosis is based upon the correlation of clinical, EUS, and cytologic features. A close interaction with the cytopathologist is required in improving the diagnostic yield. In this paper, we present an overview of the role of EUS-guided FNA and importance of close interaction with the cytopathologist. Day to day examples of different solid pancreatic lesions have been presented at the end.

Precursor lesions in pancreatic cancer: morphological and molecular pathology

Pancreatic cancer has a dismal prognosis and is the fourth most common cause of cancer related death in Western societies. In large part this is due to its typically late presentation, usually as locally advanced or metastatic disease. Identification of the non-invasive precursor lesions to pancreatic cancer raises the possibility of surgical treatment or chemoprevention at an early stage in the evolution of this disease, when more amenable to therapeutic interventions. Precursor lesions to pancreatic ductal adenocarcinoma, in particular pancreatic intraepithelial neoplasia (PanIN), have been recognised under a variety of synonyms for over 50 years. Over the past decade our understanding of the morphology, biological significance and molecular aberrations of these lesions has grown rapidly and there is now a widely accepted progression model integrating the accumulated morphological and molecular observations. Further progress is likely to be accelerated by improved mouse models of pancreatic cancer and by insight into the cancer genome gained by the International Cancer Genome Consortium (ICGC), in which an Australian consortium is leading the pancreatic cancer initiative. This review also outlines the morphological and molecular features of the other two precursors of pancreatic ductal adenocarcinoma, i.e., intraductal papillary mucinous neoplasms and mucinous cystic neoplasms.

Basics of cytology

This overview is intended to give a general outline about the basics of Cytopathology. This is a field that is gaining tremendous momentum all over the world due to its speed, accuracy and cost effectiveness. This review will include a brief description about the history of cytology from its inception followed by recent developments. Discussion about the different types of specimens, whether exfoliative or aspiration will be presented with explanation of its rule as a screening and diagnostic test. A brief description of the indications, utilization, sensitivity, specificity, cost effectiveness, speed and accuracy will be carried out. The role that cytopathology plays in early detection of cancer will be emphasized. The ability to provide all types of ancillary studies necessary to make specific diagnosis that will dictate treatment protocols will be demonstrated. A brief description of the general rules of cytomorphology differentiating benign from malignant will be presented. Emphasis on communication between clinicians and pathologist will be underscored. The limitations and potential problems in the form of false positive and false negative will be briefly discussed. Few representative examples will be shown. A brief description of the different techniques in performing fine needle aspirations will be presented. General recommendation for the safest methods and hints to enhance the sensitivity of different sample procurement will be given. It is hoped that this review will benefit all practicing clinicians that may face certain diagnostic challenges requiring the use of cytological material.

Ductal Adenocarcinoma of the Pancreas

Pancreatic ductal adenocarcinoma (PDAC) and its variants comprise between 80% and 90% of all tumors of the exocrine pancreas. Because of its silent course, late clinical manifestation, and rapid growth, it is considered a silent killer. Only 10% to 15% of cases are resectable and the 5-year survival rate remains lower than 5%. The differential diagnosis between PDAC and chronic pancreatitis is a challenge for pathologists. This article provides a guide for pathologic evaluation of PDAC specimens with the macroscopic and microscopic features of common PDAC and its variants and discusses the differential diagnosis and morphologic and immunophenotypical prognostic parameters.

Potential pitfalls in the management of primary pancreatic cystic neoplasms

Primary pancreatic cystic neoplasms (PCN) have been increasingly recognized over the last 2 decades, mainly as a result of the widespread use of modern imaging techniques in patients with abdominal complaints. Biological behavior and management greatly differ between subgroups of PCN. Accurate preoperative diagnosis is required to select the optimal management strategy for each individual patient with PCN. An in-depth knowledge of the biological, imaging, macroscopic/microscopic features, and laboratory findings of each subtype of PCN is required on the part of the clinician, in order to select a cost-effective diagnostic evaluation of the patient. Clinical judgment is also required on the part of the surgeon to select the optimal procedure and to avoid severe pitfalls in the surgical management of these neoplasms.

Primary pancreatic cystic neoplasms revisited. Part I: serous cystic neoplasms

Primary pancreatic cystic neoplasms have been recognized increasingly during the two recent decades and include mainly serous cystic neoplasms, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms. Serous cystic neoplasms represent about 30% of all cystic neoplasms of the pancreas and are characterized by their microcystic appearance (on imaging, macroscopically, and microscopically) and their benign biologic behavior. Modern diagnostic methodology allows the preoperative diagnosis with an acceptable accuracy. Currently, indications for resection of serous cystic neoplasms of the pancreas include the presence of symptoms, size > 4 cm (because these 'large' neoplasms have a more rapid growth rate and probably will soon become symptomatic), and any uncertainty about the diagnosis of a serous versus a mucinous cystic neoplasm. Resection should also be considered for lesions in the body/tail of the pancreas. Conservative treatment is a reasonable option in selected patients (for example in the presence of small, asymptomatic lesions in the pancreatic head, especially in the frail or elderly patient).

E-cadherin/beta-catenin and CD10: a limited immunohistochemical panel to distinguish pancreatic endocrine neoplasm from solid pseudopapillary neoplasm of the pancreas on endoscopic ultrasound-guided fine-needle aspirates of the pancreas

Pancreatic endocrine neoplasm (PEN) and solid pseudopapillary neoplasm of the pancreas (SPN) frequently pose diagnostic challenges. We sought to determine which markers could provide the best immunophenotypic characterization of PEN and SPN, allowing separation on limited cytology samples. We retrieved 22 resected PEN (n = 12) and SPN (n = 10) tumors to serve as a training set for the performance of extensive immunohistochemical staining. Based on these results, we selected a subset of antibodies for application to 25 fine-needle aspiration (FNA) samples from PEN (n = 16) and SPN (n = 9). Chromogranin A, synaptophysin, CD56, and progesterone receptor (PR) highlighted PEN cases in the training set; E-cadherin was noted in a membranous pattern. SPN cases were most immunoreactive for alpha(1)-antitrypsin, vimentin, CD10, and PR, with nuclear staining for beta-catenin; E-cadherin did not show a membranous pattern. Among all FNA samples tested, the immunohistochemical staining of E-cadherin (P = .0003), beta-catenin (P = .00004), and CD10 (P = .00006) demonstrated the greatest difference between PEN and SPN. The pattern of E-cadherin/beta-catenin expression was highly specific for distinguishing PEN from SPN. On limited FNA samples, the characteristic expression of E-cadherin/beta-catenin and the expression of CD10 can be used to distinguish PEN from SPN.

Endoscopic ultrasound-guided fine-needle aspiration biopsy and trucut biopsy in gastroenterology - An overview

Endoscopic ultrasound (EUS)-guided biopsies are reliable, safe and effective techniques in obtaining samples for cytological or histological examinations either as a primary procedure or in cases where other biopsy techniques have failed. Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA), as well as endoscopic ultrasound-guided trucut biopsy (EUS-TCB), has proven to be of significant value in the diagnostic evaluation of benign and malignant diseases, as well as in staging of the malignant tumours of the gastrointestinal tract and of adjacent organs. The diagnostic yield of EUS-guided biopsies depends on site, size and characteristics of target tissues as well as technical and procedural factors (type of needle, biopsy technique and material processing). Other weighting factors include expertise, training and interaction between the endosonographer and cytopathologist. Rapid on-site cytological evaluation has proven to be successful in optimising the diagnostic efficiency of EUS-FNA. A sensible alternative is to collect specimens for histological and immunohistochemical investigations in addition to the cytological smears. EUS-FNA using a 22-gauge needle is successful in harvesting core biopsies in approximately three out of four cases. Therefore, the use of 19-gauge needles for EUS-FNA or EUS-TCB may only be necessary in selected cases. The reproducibility of cytopathological diagnosis among pathologists with special experience in assessing material obtained by EUS-guided biopsies is very high. False-positive diagnosis of malignancy in EUS-guided biopsy is rare. False-negative diagnosis appears with variable frequency depending on the target tissue, technical factors and expertise of the endosonographer and cytopathologist. There are numerous challenges and pitfalls in the differential diagnostic classification of benign and malignant lesions. These problems are related to the characteristics of samples obtained by EUS-guided biopsy, as well as to the multiple diagnoses with similar or overlapping cytological or histological characteristics. The high prognostic and therapeutic relevance of the cytopathological diagnoses resulting from EUS-guided biopsy calls for a shared responsibility of an endosonographer and a cytopathologist.

Pancreatic cytopathology: a practical approach and review

CONTEXT

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

OBJECTIVE

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

CONCLUSIONS

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

Indeterminate diagnosis in fine-needle aspiration of the pancreas: reasons and clinical implications

An indeterminate diagnosis made on fine-needle aspiration (FNA) samples of the pancreatic lesions can cause dilemmas in clinical management. We retrospectively analyzed FNA features of such lesions in 65 consecutive pancreatic FNAs from 56 lesions to learn more about the sources of uncertainty and their clinical implications. A definitive diagnosis based on follow-up information was available in 50 lesions. Radiologically, 39% of the lesions showed a cystic component, and 25% of the lesions were ill-defined. Cytologically, contributing factors included scant atypical cells, coexistence of gastrointestinal epithelium, pancreatitis, poor cellular preservation, and interpretation error. Repeat sampling, as requested by clinicians prior to treatment, was performed in 33 (66%) of the 50 lesions, leading to a definitive pathologic diagnosis in 20 (61%) lesions. Seventeen lesions were eventually resected, of which a definitive preoperative diagnosis was attempted in 12 lesions via repeat sampling and was successful in seven. We concluded that indeterminate cytologic diagnosis of a pancreatic lesion often needs to be pursued for optimal management. Although intrinsic natures of a lesion such as cystic component may contribute to insufficient sampling, diagnostic certainty can be improved by proper specimen handling, interpretation, and clinical and/or radiographic correlation.

Role of endoscopic ultrasound in the diagnosis and staging of pancreatic cancer

Early diagnosis of pancreatic cancer remains a difficult task, and multiple imaging tests have been proposed over the years. The aim of this review is to describe the current role of endoscopic ultrasound (EUS) for the diagnosis and staging of patients with pancreatic cancer. A detailed search of MEDLINE between 1980 and 2007 was performed using the following keywords: pancreatic cancer, endoscopic ultrasound, diagnosis, and staging. References of the selected articles were also browsed and consulted. Despite progress made with other imaging methods, EUS is still considered to be superior for the detection of clinically suspected lesions, especially if the results of other cross-sectional imaging modalities are equivocal. The major advantage of EUS is the high negative predictive value that approaches 100%, indicating that the absence of a focal mass reliably excludes pancreatic cancer. The introduction of EUS-guided fine needle aspiration allows a preoperative diagnosis in patients with resectable cancer, as well as a confirmation of diagnosis before chemoradiotherapy for those that are not. This comprehensive review highlighted the diagnostic capabilities of EUS including the newest refinements such as contrast-enhanced EUS, EUS elastography, and 3-dimensional EUS. The place of EUS-guided biopsy is also emphasized, including the addition of molecular marker techniques.

Providing on-site diagnosis of malignancy on endoscopic-ultrasound-guided fine-needle aspirates: should it be done?

BACKGROUND

Rapid and accurate tissue diagnosis for a deep-seated malignancy would allow treating physicians to provide disease-specific interventions and help patients make early informed management decisions. Providing on-site tissue diagnosis for fine-needle aspirate samples obtained with endosonography would help develop such efficient patient management issues. Here we report our experience of prospectively providing on-site diagnosis on 485 endoscopic ultrasound fine-needle aspirate samples.

METHODS

Four hundred eighty-five endoscopic ultrasound fine-needle aspirates from the pancreas (n= 305), lymph nodes (n = 91), biliary tree (n = 47), liver (n = 15), gastrointestinal tract (n = 19), and adrenal gland (n = 8) were reviewed. For all aspirates, the cytologic diagnoses, both preliminary and final, were categorized into the following: positive for malignancy, positive for neoplastic process, suspicious for malignancy, atypical cells, reactive process, and nondiagnostic.

RESULTS

Of the 485 cases, 163 (33.6%) were diagnosed as benign, 43 (8.8%) as atypical, 21 (4.3%) as suspicious, 18 (3.7%) as positive for neoplasm, and 230 (47.4%) as malignant after final cytologic interpretation. A significantly (P < .001) higher degree of concordance was noted for unequivocal diagnosis of malignancy (196/198, 98.9%) vs nonmalignancy (200/250, 67.2%) between on-site and final cytologic diagnosis. Of the 52 discordant cases, 12 (2.6%) diagnoses were downgraded and 40 (8.9%) were upgraded from preliminary on-site diagnosis. Our overall sensitivity (87 vs 92), specificity (95% vs 100%), and accuracy (90% vs 94%) improved for final cytologic diagnosis.

CONCLUSION

On-site diagnosis of malignancy could be used to initiate informed patient management decisions. Cases where a diagnosis of malignancy is not rendered at on-site interpretation need further cytologic evaluation.

The level of carcinoembryonic antigen and the presence of mucin as predictors of cystic pancreatic mucinous neoplasia

OBJECTIVES

Characterization of pancreatic cysts using endoscopic ultrasound-guided fine-needle aspiration includes cytological interpretation and chemical analysis. We prospectively analyzed the contribution of carcinoembryonic antigen (CEA) and cytological identification of extracellular mucin as predictors of mucinous neoplasia and malignancy.

METHODS

From January 2003 to October 2005, all patients referred to the University of Virginia with cystic lesions of the pancreas underwent endoscopic ultrasound-guided fine-needle aspiration with cytological evaluation and CEA level analysis. Data were collected prospectively and confirmed by resection or tissue biopsy. Univariate and multivariate analyses were performed on the following variables with regard to their ability to predict mucinous neoplasia: age (<55 or >55 years), sex, CEA level (<300 or >300 ng/mL), and cytological appreciation of extracellular mucin (positive or negative). P values less than 0.05 were considered significant.

RESULTS

A total of 43 patients were included in this study. There were 19 men and 24 women with a mean age of 63 +/- 14 years. The only complication was pancreatitis secondary to cyst leak in one patient. Multivariate analysis confirmed CEA level greater than 300 ng/mL (P= 0.007) and the identification of mucin (P < 0.001) as significant predictors.

CONCLUSIONS

With pancreatic cyst fluid analysis, the strongest predictor of mucinous neoplasia is the presence of identifiable mucin, followed by a CEA level greater than 300 ng/mL. The workup of cystic lesions of the pancreas should include chemical analysis for the CEA level and cytological examination with particular attention to extracellular mucin.

[Endoscopic ultrasound-guided fine-needle aspiration of pancreatic cystic neoplasms: utility and limitations]

Endoscopic ultrasound-guided fine-needle aspiration has become an important method for the diagnosis of pancreatic cystic lesions. The collection, endoscopic handling and lab processing of the material must be optimally performed to avoid diagnostic pitfalls. The wide cytological spectrum of cystic pancreatic neoplasms is described especially for the diagnosis of serous cystadenoma and mucinous neoplasms in order to distinguish them from gastrointestinal contaminants. Knowledge of the clinical history, sonographic findings and even the aspirated fluid gross appearance are essential in helping the cytopathologist reach an accurate diagnosis.

Esophageal leiomyosarcoma diagnosed by endoscopic ultrasound-guided fine-needle aspiration

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has proven itself to be a reliable method for the diagnosis of gastrointestinal stromal tumors and other gastrointestinal mesenchymal neoplasms. The diagnosis and distinction of these entities remain important, as these neoplasms have different prognoses and treatment options. We present a case of a 14.5-cm esophageal mass in a 67-yr-old woman sampled by EUS-FNA. Smears showed a cellular, spindle cell lesion with marked cytologic and nuclear pleomorphism. A cell block showed neoplastic cells reacting strongly with antibodies to smooth muscle antigens and not with antibodies to keratin, CD34 and CD117. Resection confirmed the diagnosis of esophageal leiomyosarcoma. To the best of our knowledge, this represents the first reported case of an esophageal leiomyosarcoma diagnosed by EUS-FNA. Clinical, imaging, and cytologic features as well as differential diagnosis are discussed.

Fine-needle aspiration of pancreatic serous cystadenoma: cytologic features and diagnostic pitfalls

BACKGROUND

The preoperative diagnosis of pancreatic serous cystadenoma (SCA) is important because as a typically benign tumor it can be treated expectantly, whereas many other cystic tumors require excision. This study examines the cytology, clinical and radiologic features, diagnostic accuracy of fine-needle aspiration (FNA), and potential pitfalls associated with this rare tumor.

METHODS

Cytomorphologic features were retrospectively reviewed from 28 FNAs of SCA from 21 patients. FNA biopsies were guided by percutaneous computed tomographic or ultrasonographic imaging in 10 cases and by endoscopic ultrasonographic imaging in 18 cases. Corresponding histology (14 tumors) and clinical/imaging findings were also evaluated.

RESULTS

Patients typically presented with upper abdominal discomfort or asymptomatically. Radiologically, a well-demarcated, multiloculated cystic mass involving the pancreatic head or uncinate process was common. Aspirates were sparsely cellular against a clean or granular, proteinaceous background. Tumor cells formed loose clusters or monolayered sheets composed of cuboidal cells with indistinct cell borders and granular or clear cytoplasm that was often stripped from the nucleus. Nuclei were small, round, with fine chromatin and indistinct nucleoli and devoid of mitotic activity. Seven (25%) of the aspirates were initially classified as "consistent with SCA," 6 (21%) as "no malignant cells," 3 (11%) as "nondiagnostic specimen," 3 (11%) as "suspicious for malignancy," 3 (11%) as "rare atypical cells," and 6 (21%) as "probably or consistent with mucinous cystic neoplasm." Features causing diagnostic difficulty were scant cellularity, papillary groups, nuclear atypia, and columnar cells mimicking those of mucinous neoplasms. Gastrointestinal (GI) epithelium and mucin also caused confusion. The detection of intracytoplasmic glycogen (3 of 6 cases) and cyst fluid analysis (2 of 2 cases) showing low viscosity and low or undetectable levels of carcinoembryonic antigen, CA 19.9, and amylase enhanced diagnostic confidence.

CONCLUSIONS

Diagnosing SCA by FNA is challenging. Familiarity with its morphologic spectrum, use of ancillary studies, and correlation with clinical/radiologic findings greatly improves diagnostic accuracy. Contaminating GI epithelium and mucin should be distinguished from components of a mucinous neoplasm.

Intraductal papillary mucinous neoplasm of the pancreas: cytologic features predict histologic grade

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) is an increasingly recognized cystic neoplasm of the pancreas, histologically classified by the degree of epithelial atypia and by the presence or absence of invasion of the cyst wall. To the authors' knowledge, the cytologic features of this neoplasm are poorly characterized, especially with respect to tumor grade.

METHODS

Thirty-three endoscopic ultrasound (EUS)-guided pancreatic fine-needle aspiration biopsy (FNAB) samples and 1 pancreatic duct brush specimen from 25 patients with a histologically confirmed IPMN were retrospectively reviewed. Blinded to tumor grade, background mucin, inflammation, necrosis, overall cellularity, the presence of gastrointestinal-contaminating epithelium, architecture of cell clusters, and nuclear and cellular morphology were evaluated. In cases in which special stains for mucin were performed, the diagnostic utility of these stains was assessed. These cytologic features were subsequently correlated with the histologic diagnosis.

RESULTS

The 34 cytology samples represented 4 adenomas, 15 IPMN-moderate dysplasias, 7 intraductal carcinomas, and 8 IPMNs with invasive carcinoma. Extracellular mucin was present in 97% of all cases; 53% had thick, viscous, "colloid-like" mucin. Special stains for mucin were positive in 6 of 11 cases (54%), helping to identify thin mucin in only 2 cases. Gastrointestinal contamination did not appear to create diagnostic difficulty due to an apparent dual (dysplastic-nondysplastic) epithelial population, but only 4 adenomas were evaluated in this study. Necrosis distinguished IPMN with carcinoma from IPMN-adenomas and IPMN with moderate dysplasia (P < .00001), and was more often observed with invasion than IPMN-carcinoma in situ (P < .05). Tight epithelial cell clusters with hyperchromatic nuclei and a high nuclear to cytoplasmic ratio was more significant in IPMN of at least moderate dysplasia (P = .03). Pale nuclei with parachromatin clearing was found to be a nuclear feature that was suspicious for at least carcinoma in situ (P < .001). In addition, significant background inflammation (neutrophils and histiocytes) was found to be more characteristic of IPMN with at least carcinoma in situ (P = .002).

CONCLUSIONS

The presence of thick, "colloid-like" mucin is noted in half of the IPMN cases, but was not found to be specific to grade. The absence of such mucin does not exclude an IPMN. The presence of tight epithelial cell clusters is consistent with a neoplasm of at least moderate dysplasia, and abundant background inflammation and parachromatin clearing correlated with the presence of at least carcinoma in situ. Necrosis was the only feature found to be strongly suggestive of invasion.

Barrett's esophagus with high-grade dysplasia simulating metastatic adenocarcinoma in a fine needle aspiration biopsy

An endoscopic ultrasound examination, performed to rule out invasive esophageal carcinoma in a patient with a history of Barrett's esophagus with high-grade dysplasia, disclosed an enlarged paraesophageal lymph node which was aspirated. The aspirate contained markedly atypical clustered large cells that displayed prominent nucleoli and mitoses, as well as lymphoid cells, suggestive of adenocarcinoma metastatic to a lymph node. The neoplastic-appearing cells were, in fact, dysplastic glandular cells that the needle traversed en route to a reactive lymph node. The case represents a rare instance in which Barrett's esophagus with high-grade dysplasia was discerned on fine needle aspiration (FNA) biopsy and highlights a potential pitfall in FNA.

The prevalence of pancreatic intraepithelial neoplasia in pancreata with uncommon types of primary neoplasms

Pancreatic ductal adenocarcinoma is thought to develop through a series of genetic events through its purported precursor lesion, pancreatic intraepithelial neoplasia (PanIN). Little, however, is known regarding the role of possible precursor lesions in the development of other primary neoplasms of the pancreas. This study investigated the prevalence of PanIN, as defined by recent consensus statements, in pancreata with uncommon types of primary neoplasms. All pancreata resected at the University of Virginia from June 1, 1991 to March 1, 2005 for neoplasia not diagnosed as conventional ductal adenocarcinoma were reviewed and classified according to the World Health Organization's classification schema for tumors of the exocrine and endocrine pancreas. All slides from these cases were then assessed for PanIN, which was classified according to the criteria of the most recent consensus statement. Three acinar cell carcinomas (ACCs), 18 mucinous cystic neoplasms (MCNs), 24 pancreatic endocrine tumors (PETs), 12 serous cystadenomas (SCs), and 3 solid-pseudopapillary tumors (SPTs) were identified. PanIN was identified in the pancreata of 3 of 3 ACCs, 17 of 18 MCNs, 16 of 24 PETs, 10 of 12 SCs, and 2 of 3 SPTs. The degree of PanIN was noted to trend with patient age. Although the high prevalence of PanIN in pancreata concomitantly harboring certain uncommon neoplasms of the pancreas could signify its role as a precursor lesion for those neoplasms, its high prevalence throughout our series may simply be the result of a coincidental, prevalent finding seen in all pancreata, especially with aging. Because of the ubiquitous nature of PanIN, it should not be used histologically to assist in the diagnosis and subclassification of pancreatic neoplasia.

Endoscopic ultrasound-guided fine needle aspiration cytology of pancreatic neuroendocrine tumours: cytomorphological and immunocytochemical evaluation

OBJECTIVES

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) is increasingly used in preoperative localization and diagnosis of pancreatic neoplasms including neuroendocrine tumours (NETs). The objective of the present study was to identify the cytological features of pancreatic NETs obtained by EUS-FNA.

METHODS

The study group consisted of nine cases of pancreatic tumours correctly diagnosed or strongly suggestive of NETs based on EUS-FNA. Cytological smears were retrospectively reviewed. The clinical data and immunocytochemical stains applied to the cell block preparations were also reviewed and examined.

RESULTS

All cases except one showed characteristic cytomorphological features sufficient for their recognition and separation from pancreatic adenocarcinoma and other lesions. The most helpful cytological features that facilitated the cytological diagnosis of NET were a richly cellular aspirate with a monotonous, poorly cohesive population of small cells with a speckled or dusty chromatin pattern and plasmacytoid morphology. The neuroendocrine differentiation of these tumours was further confirmed by immunocytochemistry.

CONCLUSION

EUS-FNA is a valuable method in the recognition of pancreatic NETs. By adherence to the characteristic cytomorphological criteria of pancreatic NET together with collection of suitable material for ancillary immunocytochemical stains, cytopathologists could reach a correct diagnosis in most instances.

Endoscopic ultrasound-guided FNA biopsy of bile duct and gallbladder: analysis of 53 cases

OBJECTIVE

Endoscopic retrograde cholangiopancreaticography (ERCP)-guided brushing has been the standard of practice for surveillance and detection of carcinoma in the biliary tree. Few studies have evaluated the role of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in diagnosing clinically suspected cholangiocarcinoma. The role of this method in diagnosing clinically suspected gallbladder malignancies has not been extensively evaluated in the USA. This study investigates the role of EUS-FNA in the diagnosis of clinically suspected biliary tree and gallbladder malignancies in a large patient series.

METHODS

EUS-FNAs were obtained from 46 bile duct and seven gallbladder lesions. On-site rapid interpretation was provided using air-dried Diff Quik stained smears. In addition, alcohol fixed Papanicoloau stained smears and Thin Prep preparations (Cytye Corp., Marlborough, MA, USA) were evaluated before providing a final cytological diagnosis. Tissue biopsies and/or clinical follow-up were used as the standards to determine operating characteristics for EUS-FNA.

RESULTS

The mean ages for bile duct and gallbladder lesions were 66 years (range: 37-84 years), and 69 years (range 49-86 years), respectively. All cases diagnosed as suspicious/malignant on preliminary evaluation were confirmed on final cytological interpretation (27/27). The operating characteristics show that EUS-FNA is highly specific (100%) with sensitivity rates of 87% and 80% from clinically suspected malignancies of biliary tract and gallbladder, respectively. Sampling error in three cases and associated acute inflammation in two cases resulted in false-negative diagnoses.

CONCLUSIONS

EUS-FNA of biliary tree and gallbladder carcinoma is highly specific and should be considered for evaluation of clinically suspicious lesions. Marked inflammation may result in false-negative diagnoses.

Cytology of pancreatic acinar cell carcinoma

Acinar cell carcinoma (ACC) of the pancreas is extremely uncommon and its cytologic features have rarely been described. We describe the cytologic features of cases we have seen, review the literature regarding its cytologic features and discuss the pitfalls that may be encountered and the use of immunohistochemistry for its diagnosis. We searched our databases for all cases of histologically confirmed pancreatic ACC which had undergone prior fine needle aspiration (FNA) of the primary pancreatic lesion. The clinical histories, radiographic and sonographic findings, cytologic features, original cytologic diagnoses, and final histologic diagnoses were reviewed. Four cases of pancreatic ACC were found that had undergone FNA prior to histologic confirmation of the diagnoses. They were from 2 men and 2 women aged 50-75 yr. All masses were in the head of the pancreas, 2 had apparent peri-pancreatic adenopathy and 1 had an apparent liver metastasis. On review, all 4 had had diagnostic material on cytology samples. Original cytologic diagnoses included "acinar cell carcinoma," "pancreatic endocrine tumor," "favor neuroendocrine tumor, low-grade" and "non-diagnostic specimen." The cytologic features included small to moderate-sized loose groups with numerous single cells, prominent acinar formation, little anisonucleosis and prominent nucleoli. The cytologic features showed significant overlap with those of pancreatic endocrine tumors.

Cytologic diagnosis of pancreatic endocrine tumors by endoscopic ultrasound-guided fine-needle aspiration: A review

Precise localization and diagnosis of pancreatic endocrine tumors (PETs) is important, because pancreatic PETs have different clinical and biological behavior and treatment modalities than do exocrine pancreatic tumors. In contrast to the much more common exocrine adenocarcinomas, cytologic studies of PET are relatively rare and many cytopathologists lack experience with the cytomorphologic features of these tumors.During the last 10 yr, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has matured into an accurate, highly sensitive, and cost-effective modality for the preoperative localization of pancreatic PETs. This has resulted in an increased number of PETs first sampled as cytology specimens. This manuscript focuses on the cytomorphologic features most suggestive of pancreatic PETs, differential diagnosis, and diagnostic pitfalls of PETs. The technical development of EUS-guided FNA and the ancillary studies for pancreatic PETs are also reviewed. The data summarized in this review indicate that EUS-FNA is a valuable method in the recognition of pancreatic PETs and in most cases cytopathologists could reach a correct diagnosis of these tumors, including their hormone producing capability on aspirated cytologic material.