- Email: [email protected]
What I need to know and what I need to do if I do not have a cytopathologist present for the procedure
What I need to know and what I need to do if I do not have a cytopathologist present for the procedure `s, MD, PhD, Manel Sole ´, MD, PhD, Glo ` ria Ferna ´ndez-Esparrach, MD, PhD Angels Gine Barcelona, Spain
INTRODUCTION There is evidence enough in the literature to assert that on-site cytopathologic interpretation of the sample improves the diagnostic yield of EUS-guided FNA (EUS-FNA).1,2 Moreover, it is known that the presence of an attending cytopathologist during the procedure is cost effective,3,4 although this point may vary among different countries and institutions. Unfortunately, an on-site cytopathologist is not always available and increases the cost of the procedure. An alternative strategy could be to have an on-site cytotechnologist (able to interpret adequacy) who would submit difficult cases to the cytologist or bring the sample to the laboratory for immediate review while the endosonographer is waiting to know if more passes are necessary. Because pancreatic lesions are the most difficult to diagnose, a theoretically useful approach could be to concentrate them within the week and try to have an attendant cytopathologist for this specific group of patients. However, none of these strategies has been formally tested or compared with the others. Also, some devices consisting of a microscope provided with a digital camera can transmit the images to the cytopathologist’s desktop. In this case, what is necessary to do in the EUS room is only to prepare the smears and drive the microscope. If none of the different options mentioned above is available, then the endosonographer must prepare the smears and be able to recognize the adequacy of the sample. Therefore, what do we need to know and what do we need to do when a cytopathologist is not present for the procedure?
DIAGNOSTIC ORIENTATION Some crucial points concerning diagnostic orientation have to be taken into account when evaluating a sample obtained by EUS-FNA, either with or without an in-room cytopathologist: d Clinical data must be clear enough to evaluate the importance of obtaining the cytologic diagnosis as well as the influence on patient management. Other important information to know is the availability or unavailability
´ ndez-Esparrach disclosed ` s, M. Sole ´ , and G. Ferna DISCLOSURE: A. Gine no financial relationships relevant to this publication. Copyright ª 2009 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2008.12.042
S142 GASTROINTESTINAL ENDOSCOPY Volume 69, No. 2 : 2009
d
of other techniques or the existence of inconclusive previous results. To improve the diagnostic field of EUS-FNA, it is very important to establish a diagnosis of suspicion based on clinical data and morphologic findings, because an additional sample may be needed for further analysis in the laboratory. Pancreatic adenocarcinomas and lymph-node metastases of known origin are usually diagnosed with smears alone. However, if there is a suspicion of neuroendocrine tumor, metastasis of unknown origin, mesenchymal neoplasms, or in any atypical case, immunocytochemistry will probably be needed, and enough material should be provided. If a lymphoma is suspected, a separate sample in saline solution for flow-cytometry immunophenotyping is preferable.5 Simple molecular determinations can be performed from very small samples, such as those obtained from the needle rinsing.3,6
EUS-FNA TECHNIQUE Technical details for EUS-guided FNA will not be discussed in this article. Two practical issues to increase the diagnostic yield of EUS-FNA are the following: d Aspirate the periphery of the lesion and skip areas of cystic appearance to avoid necrosis. d Thin needles (up to 25 gauge) may be useful for highly cellular targets such as lymph nodes and neuroendocrine tumors or when obtained specimens are very bloody.
MORPHOLOGIC EVALUATION It is known that immediate processing of the obtained specimen has a major impact on the diagnostic performance of EUS-FNA.1,7 If on-site cytopathology evaluation is not available, the endosonographer must know how to prepare the smears and fix them, as well as how to keep the sample for cell block procedures.
PREPARATION OF THE SMEARS Smears are prepared by expelling the material with air using the syringe or reintroducing the stylet in the needle and pushing forward, which allows the distribution of the sample onto several slides. Either way, smears have to be prepared gently, without pressure, to avoid crushing artifacts. Thin smears are preferable; therefore, several slides are necessary for bloody or very thick specimens (Fig. 1). Careful www.giejournal.org
`s et al Gine
No cytopathologist present
Figure 1. Steps of EUS-FNA sample processing. A, Lung adenocarcinoma (Diff-Quick, orig. mag. 400) and B, Lung adenocarcinoma (Papanicolau’s, orig. mag. 400).
inspection of the sample can disclose small tissular fragments and clots that will disturb the procedure. These should be picked up with a forceps or a needle, smeared onto separate slides, and then transferred to a container with saline solution or a fixative for further cell block preparation (Fig. 2). Since the fixation of the smears depends on the stains that will be used, previous consultation with the referral cytopathologist is mandatory. The aspirate has to be fixed immediately to avoid cellular distortion. d Papanicolau’s stain: wet fixation (96% alcohol or fixative spray); fixation has to be immediate to avoid drying. www.giejournal.org
Romanowsky stainings (May-Gru ¨ nwald Giemsa, DiffQuick) and hematoxylin-eosin: air-drying. Fixation with alcohol is also suitable for most immunocytochemical studies, particularly when few markers are necessary (ie, c-kit for GI stromal tumors). Both methods of fixation (wet and air) allow for DNA extraction if necessary, by scraping the slides. Simple but more expensive alternatives for an adequate preservation of the specimen are thin-layer fluid-based technologies. These systems allow excellent preservation of cellular morphology and nucleic acids.8 However, their d
Volume 69, No. 2 : 2009 GASTROINTESTINAL ENDOSCOPY S143
`s et al Gine
No cytopathologist present
Figure 2. Cell block preparation in the EUS room, and some of the possibilities it offers after laboratory processing (A, H&E orig. mag. 10; B, H&E, orig. mag. 100; C and D, immunohystochemical stain, orig. mag. 100).
performance for cytologic diagnosis of FNA samples is still under debate, and their use for this particular application is limited to some laboratories as well. The most widespread system is ThinPrep. In this case, the aspirated material is directly ejected into a container filled with a specific fixative that permits transportation of the specimen to the laboratory for subsequent processing and interpretation.9 Special cases are cystic lesions. The appearance of the fluid, by itself, cannot be used to make a conclusive diagnosis, but it should be recorded because it provides excellent evidence for the mucinous or serous nature of the cyst. In situ endoscopic examination does not provide significant advantages because of the scarcity of cells. However, the sample must be quickly sent to the laboratory to avoid degradation. If thin-layer fluid-based technologies are used, it has to be kept in mind that the preservative interferes with the recognition of mucus, one of the diagnostic clues in pancreatic cysts. The aspirated fluid should be sent for cytologic evaluation as well as for amylase and tumor markers determinations.10,11 S144 GASTROINTESTINAL ENDOSCOPY Volume 69, No. 2 : 2009
PREPARATION OF THE CELL BLOCK The FNA specimen is usually composed by single cells and tissue fragments. Preparation of the material for further cell block evaluation is done by recovering any tissue fragment or clot from the slides and rinsing the needle with sterile saline solution and keeping everything together in a tube for processing in the laboratory (Fig. 2). As previously stated, the cell block is a very useful diagnostic tool in many situations. In particular cases, specific passes should be performed for this purpose, together with rinsing of the needle and the fragments and clots recovered from the slides.
EVALUATION OF THE ADEQUACY OF THE EUSFNA SAMPLE This is the critical point when on-site cytopathology evaluation is absent. It has been demonstrated that, as expected, www.giejournal.org
`s et al Gine
even trained endosonographers (with extensive experience viewing cytologic samples alongside cytopathologists or cytotechnologists and medical school training in pathology) are less reliable than cytotechnologists in evaluating the sample.12 Visual inspection of the sample may be a good marker of its quality (a serosanguineous sample with evidence of tissue within it). However, to recognize cells and mainly to differentiate contaminating cells of the digestive wall from the cells of the target lesion may be impossible for the endosonographer. In this sense, contaminating cells from the needle path is one of the most common pitfalls in immediate evaluation, even for expert cytologists. Cells of the gastroduodenal wall are particularly disturbing because gastric mucosa can mimic mucinous epithelium and duodenal mucosa is similar to pancreatic-ductal epithelium. This fact renders the evaluation of the samples obtained by EUS-FNA more difficult, since it is not enough to state that cells are present but that they are representative of the target lesion. Well-differentiated adenocarcinomas may be extremely difficult to distinguish from normal mucosa. Because of the difficulty of certifying the adequacy of the sample when the cytopathologist is not present, and as an attempt to minimize the number of definitive undiagnosed patients due to this problem, an effort has been made to assess how many passes are required to maximize the diagnostic yield of EUS-FNA. This is the crucial question when an on-site cytopathologist is not present. Several studies tried to assess a reliable answer. The factors that influence the number of passes needed are the following: sonographic characteristics of the lesion, pretest probability of the expected diagnosis, the presence of a cytopathologist or a cytotechnologist during the procedure, and the level of cytologic expertise.13 Retrospective studies found the optimal number of passes to range from 2 to 6.13 For lymph nodes, up to 3 passes were prospectively shown to be optimal.14 In a study performed by Leblanc et al,13 at least 7 passes into pancreatic and miscellaneous lesions (mainly mediastinal, perirectal, and subepithelial masses) and 5 passes into lymph nodes were necessary to get a high degree of certainty for making a correct diagnosis. Another study, performed in 121 patients, showed that, without a cytopathologist in attendance, 5 to 6 passes are needed for the diagnosis of pancreatic masses and 2 to 3 for liver metastases and lymph nodes. The investigators also demonstrated that, with this approach, there was a 10% to 15% reduction in definitive diagnosis, as well as extraprocedure time, increased risk, and additional needles compared with the same procedure when it was performed with in-room cytopathologic evaluation.15 Abbreviation: EUS-FNA, EUS-guided FNA.
www.giejournal.org
No cytopathologist present
REFERENCES 1. Klapman JB, Logron˜o R, Dye ChD, et al. Clinical impact of on-site cytopathology interpretation on endoscopic ultrasound-guided fine needle aspiration. Am J Gastroenterol 2003;98:1289-94. 2. Chang KJ. Maximizing the yield of EUS-guided fine-needle aspiration. Gastrointest Endosc 2002;56(Suppl):28-34. 3. Pellise´ M, Castells A, Gine`s A, et al. Clinical usefulness of KRAS mutational analysis in the diagnosis of pancreatic adenocarcinoma by means of endosonography-guided fine-needle aspiration biopsy. Alimnet Pharmacol Ther 2003;17:1299-307. 4. Nasuti JF, Gupta PK, Baloch ZW. Diagnostic value and cost-effectiveness of on-site evaluation of fine-needle aspiration specimens: review of 5,688 cases. Diagn Cytopathol 2002;27:1-4. 5. Ribeiro A, Vazquez-Sequeiros E, Wiersema LM, et al. EUS-guided fineneedle aspiration combined with flow cytometry and immunocytochemistry in the diagnosis of lymphoma. Gastrointest Endosc 2001;53:485-91. 6. Wallace MB, Block MI, Gillanders W, et al. Accurate molecular detection of non-small cell lung cancer metastases in mediastinal lymph nodes sampled by endoscopic ultrasound-guided needle aspiration. Chest 2005;127:418-20. 7. Jhala NC, Jhala D, Eltoum I, et al. Endoscopic ultrasound-guided fineneedle aspiration biopsy: a powerful tool to obtain samples from small lesions. Cancer Cytopathol 2004;102:239-46. 8. Frossard JL, Amouyal P, Amouyal G, et al. Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions. Am J Gastroenterol 2003;98:1516-24. 9. Maksem JA, Weidmann J. Specialized preparative devices are not needed for liquid-based, thin-layer cytology: an alternate manual method using a metastable alcoholic gel. Diagn Cytopathol 2001;25: 262-4. 10. O’Toole D, Palazzo L, Hammel P, et al. Macrocystic pancreatic cystadenoma: the role of EUS and cystic fluid analysis in distinguishing mucinous and serous lesions. Gastrointest Endosc 2004;59:823-9. 11. Brugge WR. Should all pancreatic cystic lesions be resected? Cyst-fluid analysis in the differential diagnosis of pancreatic cystic lesions: a meta-analysis. Gastrointest Endosc 2005;62:390-1. 12. Savoy AD, Raimondo M, Woosward TA, et al. Can endosonographers evaluate on-site cytologic adequacy? A comparison with cytotechnologists. Gastrointest Endosc 2007;65:953-7. 13. LeBlanc JK, Ciaccia D, Al-Assi MT, et al. Optimal number of EUS-guided fine needle passes needed to obtain a correct diagnosis. Gastrointest Endosc 2004;59:475-81. 14. Wallace MB, Kennedy T, Durkalski V, et al. Randomized controlled trial of EUS-guided fine needle aspiration techniques for the detection of malignant lymphadenopathy. Gastrointest Endosc 2001;54: 441-7. 15. Erickson RA, Sayage-Rabie L, Beissner S. Factors predicting the number of EUS-guided fine-needle passes for diagnosis of pancreatic malignancies. Gastrointest Endosc 2000;51:184-90.
Endoscopy Unit (A.G., G.F.-E.), Department of Gastroenterology, ICMDM, IDIBAPS, CiberEHD, Barcelona, Department of Pathology (M.S.), CBD, Hospital Clı´nic, Barcelona, Spain. This article is from a meeting and has not undergone the GIE peer review process.
Volume 69, No. 2 : 2009 GASTROINTESTINAL ENDOSCOPY S145
INTRODUCTION There is evidence enough in the literature to assert that on-site cytopathologic interpretation of the sample improves the diagnostic yield of EUS-guided FNA (EUS-FNA).1,2 Moreover, it is known that the presence of an attending cytopathologist during the procedure is cost effective,3,4 although this point may vary among different countries and institutions. Unfortunately, an on-site cytopathologist is not always available and increases the cost of the procedure. An alternative strategy could be to have an on-site cytotechnologist (able to interpret adequacy) who would submit difficult cases to the cytologist or bring the sample to the laboratory for immediate review while the endosonographer is waiting to know if more passes are necessary. Because pancreatic lesions are the most difficult to diagnose, a theoretically useful approach could be to concentrate them within the week and try to have an attendant cytopathologist for this specific group of patients. However, none of these strategies has been formally tested or compared with the others. Also, some devices consisting of a microscope provided with a digital camera can transmit the images to the cytopathologist’s desktop. In this case, what is necessary to do in the EUS room is only to prepare the smears and drive the microscope. If none of the different options mentioned above is available, then the endosonographer must prepare the smears and be able to recognize the adequacy of the sample. Therefore, what do we need to know and what do we need to do when a cytopathologist is not present for the procedure?
DIAGNOSTIC ORIENTATION Some crucial points concerning diagnostic orientation have to be taken into account when evaluating a sample obtained by EUS-FNA, either with or without an in-room cytopathologist: d Clinical data must be clear enough to evaluate the importance of obtaining the cytologic diagnosis as well as the influence on patient management. Other important information to know is the availability or unavailability
´ ndez-Esparrach disclosed ` s, M. Sole ´ , and G. Ferna DISCLOSURE: A. Gine no financial relationships relevant to this publication. Copyright ª 2009 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2008.12.042
S142 GASTROINTESTINAL ENDOSCOPY Volume 69, No. 2 : 2009
d
of other techniques or the existence of inconclusive previous results. To improve the diagnostic field of EUS-FNA, it is very important to establish a diagnosis of suspicion based on clinical data and morphologic findings, because an additional sample may be needed for further analysis in the laboratory. Pancreatic adenocarcinomas and lymph-node metastases of known origin are usually diagnosed with smears alone. However, if there is a suspicion of neuroendocrine tumor, metastasis of unknown origin, mesenchymal neoplasms, or in any atypical case, immunocytochemistry will probably be needed, and enough material should be provided. If a lymphoma is suspected, a separate sample in saline solution for flow-cytometry immunophenotyping is preferable.5 Simple molecular determinations can be performed from very small samples, such as those obtained from the needle rinsing.3,6
EUS-FNA TECHNIQUE Technical details for EUS-guided FNA will not be discussed in this article. Two practical issues to increase the diagnostic yield of EUS-FNA are the following: d Aspirate the periphery of the lesion and skip areas of cystic appearance to avoid necrosis. d Thin needles (up to 25 gauge) may be useful for highly cellular targets such as lymph nodes and neuroendocrine tumors or when obtained specimens are very bloody.
MORPHOLOGIC EVALUATION It is known that immediate processing of the obtained specimen has a major impact on the diagnostic performance of EUS-FNA.1,7 If on-site cytopathology evaluation is not available, the endosonographer must know how to prepare the smears and fix them, as well as how to keep the sample for cell block procedures.
PREPARATION OF THE SMEARS Smears are prepared by expelling the material with air using the syringe or reintroducing the stylet in the needle and pushing forward, which allows the distribution of the sample onto several slides. Either way, smears have to be prepared gently, without pressure, to avoid crushing artifacts. Thin smears are preferable; therefore, several slides are necessary for bloody or very thick specimens (Fig. 1). Careful www.giejournal.org
`s et al Gine
No cytopathologist present
Figure 1. Steps of EUS-FNA sample processing. A, Lung adenocarcinoma (Diff-Quick, orig. mag. 400) and B, Lung adenocarcinoma (Papanicolau’s, orig. mag. 400).
inspection of the sample can disclose small tissular fragments and clots that will disturb the procedure. These should be picked up with a forceps or a needle, smeared onto separate slides, and then transferred to a container with saline solution or a fixative for further cell block preparation (Fig. 2). Since the fixation of the smears depends on the stains that will be used, previous consultation with the referral cytopathologist is mandatory. The aspirate has to be fixed immediately to avoid cellular distortion. d Papanicolau’s stain: wet fixation (96% alcohol or fixative spray); fixation has to be immediate to avoid drying. www.giejournal.org
Romanowsky stainings (May-Gru ¨ nwald Giemsa, DiffQuick) and hematoxylin-eosin: air-drying. Fixation with alcohol is also suitable for most immunocytochemical studies, particularly when few markers are necessary (ie, c-kit for GI stromal tumors). Both methods of fixation (wet and air) allow for DNA extraction if necessary, by scraping the slides. Simple but more expensive alternatives for an adequate preservation of the specimen are thin-layer fluid-based technologies. These systems allow excellent preservation of cellular morphology and nucleic acids.8 However, their d
Volume 69, No. 2 : 2009 GASTROINTESTINAL ENDOSCOPY S143
`s et al Gine
No cytopathologist present
Figure 2. Cell block preparation in the EUS room, and some of the possibilities it offers after laboratory processing (A, H&E orig. mag. 10; B, H&E, orig. mag. 100; C and D, immunohystochemical stain, orig. mag. 100).
performance for cytologic diagnosis of FNA samples is still under debate, and their use for this particular application is limited to some laboratories as well. The most widespread system is ThinPrep. In this case, the aspirated material is directly ejected into a container filled with a specific fixative that permits transportation of the specimen to the laboratory for subsequent processing and interpretation.9 Special cases are cystic lesions. The appearance of the fluid, by itself, cannot be used to make a conclusive diagnosis, but it should be recorded because it provides excellent evidence for the mucinous or serous nature of the cyst. In situ endoscopic examination does not provide significant advantages because of the scarcity of cells. However, the sample must be quickly sent to the laboratory to avoid degradation. If thin-layer fluid-based technologies are used, it has to be kept in mind that the preservative interferes with the recognition of mucus, one of the diagnostic clues in pancreatic cysts. The aspirated fluid should be sent for cytologic evaluation as well as for amylase and tumor markers determinations.10,11 S144 GASTROINTESTINAL ENDOSCOPY Volume 69, No. 2 : 2009
PREPARATION OF THE CELL BLOCK The FNA specimen is usually composed by single cells and tissue fragments. Preparation of the material for further cell block evaluation is done by recovering any tissue fragment or clot from the slides and rinsing the needle with sterile saline solution and keeping everything together in a tube for processing in the laboratory (Fig. 2). As previously stated, the cell block is a very useful diagnostic tool in many situations. In particular cases, specific passes should be performed for this purpose, together with rinsing of the needle and the fragments and clots recovered from the slides.
EVALUATION OF THE ADEQUACY OF THE EUSFNA SAMPLE This is the critical point when on-site cytopathology evaluation is absent. It has been demonstrated that, as expected, www.giejournal.org
`s et al Gine
even trained endosonographers (with extensive experience viewing cytologic samples alongside cytopathologists or cytotechnologists and medical school training in pathology) are less reliable than cytotechnologists in evaluating the sample.12 Visual inspection of the sample may be a good marker of its quality (a serosanguineous sample with evidence of tissue within it). However, to recognize cells and mainly to differentiate contaminating cells of the digestive wall from the cells of the target lesion may be impossible for the endosonographer. In this sense, contaminating cells from the needle path is one of the most common pitfalls in immediate evaluation, even for expert cytologists. Cells of the gastroduodenal wall are particularly disturbing because gastric mucosa can mimic mucinous epithelium and duodenal mucosa is similar to pancreatic-ductal epithelium. This fact renders the evaluation of the samples obtained by EUS-FNA more difficult, since it is not enough to state that cells are present but that they are representative of the target lesion. Well-differentiated adenocarcinomas may be extremely difficult to distinguish from normal mucosa. Because of the difficulty of certifying the adequacy of the sample when the cytopathologist is not present, and as an attempt to minimize the number of definitive undiagnosed patients due to this problem, an effort has been made to assess how many passes are required to maximize the diagnostic yield of EUS-FNA. This is the crucial question when an on-site cytopathologist is not present. Several studies tried to assess a reliable answer. The factors that influence the number of passes needed are the following: sonographic characteristics of the lesion, pretest probability of the expected diagnosis, the presence of a cytopathologist or a cytotechnologist during the procedure, and the level of cytologic expertise.13 Retrospective studies found the optimal number of passes to range from 2 to 6.13 For lymph nodes, up to 3 passes were prospectively shown to be optimal.14 In a study performed by Leblanc et al,13 at least 7 passes into pancreatic and miscellaneous lesions (mainly mediastinal, perirectal, and subepithelial masses) and 5 passes into lymph nodes were necessary to get a high degree of certainty for making a correct diagnosis. Another study, performed in 121 patients, showed that, without a cytopathologist in attendance, 5 to 6 passes are needed for the diagnosis of pancreatic masses and 2 to 3 for liver metastases and lymph nodes. The investigators also demonstrated that, with this approach, there was a 10% to 15% reduction in definitive diagnosis, as well as extraprocedure time, increased risk, and additional needles compared with the same procedure when it was performed with in-room cytopathologic evaluation.15 Abbreviation: EUS-FNA, EUS-guided FNA.
www.giejournal.org
No cytopathologist present
REFERENCES 1. Klapman JB, Logron˜o R, Dye ChD, et al. Clinical impact of on-site cytopathology interpretation on endoscopic ultrasound-guided fine needle aspiration. Am J Gastroenterol 2003;98:1289-94. 2. Chang KJ. Maximizing the yield of EUS-guided fine-needle aspiration. Gastrointest Endosc 2002;56(Suppl):28-34. 3. Pellise´ M, Castells A, Gine`s A, et al. Clinical usefulness of KRAS mutational analysis in the diagnosis of pancreatic adenocarcinoma by means of endosonography-guided fine-needle aspiration biopsy. Alimnet Pharmacol Ther 2003;17:1299-307. 4. Nasuti JF, Gupta PK, Baloch ZW. Diagnostic value and cost-effectiveness of on-site evaluation of fine-needle aspiration specimens: review of 5,688 cases. Diagn Cytopathol 2002;27:1-4. 5. Ribeiro A, Vazquez-Sequeiros E, Wiersema LM, et al. EUS-guided fineneedle aspiration combined with flow cytometry and immunocytochemistry in the diagnosis of lymphoma. Gastrointest Endosc 2001;53:485-91. 6. Wallace MB, Block MI, Gillanders W, et al. Accurate molecular detection of non-small cell lung cancer metastases in mediastinal lymph nodes sampled by endoscopic ultrasound-guided needle aspiration. Chest 2005;127:418-20. 7. Jhala NC, Jhala D, Eltoum I, et al. Endoscopic ultrasound-guided fineneedle aspiration biopsy: a powerful tool to obtain samples from small lesions. Cancer Cytopathol 2004;102:239-46. 8. Frossard JL, Amouyal P, Amouyal G, et al. Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions. Am J Gastroenterol 2003;98:1516-24. 9. Maksem JA, Weidmann J. Specialized preparative devices are not needed for liquid-based, thin-layer cytology: an alternate manual method using a metastable alcoholic gel. Diagn Cytopathol 2001;25: 262-4. 10. O’Toole D, Palazzo L, Hammel P, et al. Macrocystic pancreatic cystadenoma: the role of EUS and cystic fluid analysis in distinguishing mucinous and serous lesions. Gastrointest Endosc 2004;59:823-9. 11. Brugge WR. Should all pancreatic cystic lesions be resected? Cyst-fluid analysis in the differential diagnosis of pancreatic cystic lesions: a meta-analysis. Gastrointest Endosc 2005;62:390-1. 12. Savoy AD, Raimondo M, Woosward TA, et al. Can endosonographers evaluate on-site cytologic adequacy? A comparison with cytotechnologists. Gastrointest Endosc 2007;65:953-7. 13. LeBlanc JK, Ciaccia D, Al-Assi MT, et al. Optimal number of EUS-guided fine needle passes needed to obtain a correct diagnosis. Gastrointest Endosc 2004;59:475-81. 14. Wallace MB, Kennedy T, Durkalski V, et al. Randomized controlled trial of EUS-guided fine needle aspiration techniques for the detection of malignant lymphadenopathy. Gastrointest Endosc 2001;54: 441-7. 15. Erickson RA, Sayage-Rabie L, Beissner S. Factors predicting the number of EUS-guided fine-needle passes for diagnosis of pancreatic malignancies. Gastrointest Endosc 2000;51:184-90.
Endoscopy Unit (A.G., G.F.-E.), Department of Gastroenterology, ICMDM, IDIBAPS, CiberEHD, Barcelona, Department of Pathology (M.S.), CBD, Hospital Clı´nic, Barcelona, Spain. This article is from a meeting and has not undergone the GIE peer review process.
Volume 69, No. 2 : 2009 GASTROINTESTINAL ENDOSCOPY S145