A precise diagnosis of the nature of pancreatic cystic neoplasm (PCN) is crucial since it determines the patients in need of rapid surgical resection as well as those who can be followed up, and, accordingly, the frequency and modalities of surveillance. Endoscopic ultrasound (EUS) and especially fine needle aspiration (FNA) are invasive methods, with specific adverse events occurring in 2.7-5%. Thus, they should only be used as a third-line tool in the absence of characteristic radiographic features on computed tomography (CT) scan and magnetic resonance imaging (MRI). The most difficult aspects of differential diagnosis are: intraductal papillary mucinous neoplasm (IPMN) versus chronic pancreatitis; unifocal IPMN versus serous cystic neoplasm (SCN); macrocystic SCN versus mucinous cystic neoplasm (MCN); cystic neuroendocrine tumors versus MCN; solid serous cystadenoma versus neuroendocrine tumors versus small solid pseudopapillary tumors; pseudocyst versus MCN; low-grade, high-grade, or invasive IPMN. When classical radiological and EUS features are not conclusive, EUS-FNA may be helpful by analyzing cytological, chemical, and/or molecular data. The addition of EUS-FNA to CT scan and MRI increased the overall accuracy for diagnosing PCN by 36 and 54%, respectively. Analysis of molecular markers in pancreatic cyst fluid might increase the limited accuracy of EUS-FNA by using cytology and chemical and/or tumor marker analysis alone. Current evidence suggests that contrast-enhanced EUS (CH-EUS) is highly accurate for distinguishing non-neoplastic cysts from neoplastic cysts. CH-EUS might also be useful for distinguishing mural epithelial nodules from mucinous clots. Needle-based confocal laser endomicroscopy (nCLE) images a target tissue at a subcellular level of resolution, providing real-time in-vivo optical biopsy. nCLE is feasible during EUS-FNA and allows in-vivo diagnosis of PCN with high accuracy. In conclusion, EUS is a third-line tool in the diagnosis of PCN. Clinical context as well as careful evaluation of CT scan and magnetic resonance cholangiopancreatography images by specialized radiologists are crucial in the diagnosis process. Nowadays it is inconceivable to skip these steps.

1.
Laurent L, et al: Estimation of the prevalence of intraductal papillary mucinous neoplasm of the pancreas in the French population through patients waiting for liver transplantation. United European Gastroenterol J 2017;5:499-503.
2.
ASGE Standards of Practice Committee; Early DS, et al: Adverse events associated with EUS and EUS with FNA. Gastrointest Endosc 2013;77:839-843.
3.
Brugge WR, et al: Diagnosis of pancreatic cystic neoplasms: a report of the cooperative pancreatic cyst study. Gastroenterology 2004;126:1330-1336.
4.
Ahmad NA, et al: Interobserver agreement among endosonographers for the diagnosis of neoplastic versus non-neoplastic pancreatic cystic lesions. Gastrointest Endosc 2003;58:59-64.
5.
Song MH, et al: EUS in the evaluation of pancreatic cystic lesions. Gastrointest Endosc 2003;57:891-896.
6.
Koito K, et al: Solitary cystic tumor of the pancreas: EUS-pathologic correlation. Gastrointest Endosc 1997;45:268-276.
7.
Cohen-Scali F, et al: Discrimination of unilocular macrocystic serous cystadenoma from pancreatic pseudocyst and mucinous cystadenoma with CT: initial observations. Radiology 2003;228:727-733.
8.
Kim KW, et al: Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis. Ann Surg 2014;259:72-81.
9.
Tanaka M, et al: Revisions of international consensus Fukuoka guidelines for the management of IPMN of the pancreas. Pancreatology 2017;17:738-753.
10.
Zhong N, et al: Histologic and imaging features of mural nodules in mucinous pancreatic cysts. Clin Gastroenterol Hepatol 2012;10:192-198, 198.e1-2.
11.
Lim LG, et al: Factors determining diagnostic yield of endoscopic ultrasound guided fine-needle aspiration for pancreatic cystic lesions: a multicentre Asian study. Dig Dis Sci 2013;58:1751-1757.
12.
Rogart JN, et al: Cyst wall puncture and aspiration during EUS-guided fine needle aspiration may increase the diagnostic yield of mucinous cysts of the pancreas. J Clin Gastroenterol 2011;45:164-169.
13.
Levy MJ, et al: Endoscopic ultrasound-guided trucut biopsy of the cyst wall for diagnosing cystic pancreatic tumors. Clin Gastroenterol Hepatol 2005;3:974-979.
14.
van der Waaij LA, van Dullemen HM, Porte RJ: Cyst fluid analysis in the differential diagnosis of pancreatic cystic lesions: a pooled analysis. Gastrointest Endosc 2005;62:383-389.
15.
O'Toole D, et al: Macrocystic pancreatic cystadenoma: the role of EUS and cyst fluid analysis in distinguishing mucinous and serous lesions. Gastrointest Endosc 2004;59:823-829.
16.
Farrell JJ, Fernandez-del Castillo C: Pancreatic cystic neoplasms: management and unanswered questions. Gastroenterology 2013;144:1303-1315.
17.
Thosani N, et al: Role of EUS-FNA-based cytology in the diagnosis of mucinous pancreatic cystic lesions: a systematic review and meta-analysis. Dig Dis Sci 2010;55:2756-2766.
18.
Thornton GD, et al: Endoscopic ultrasound guided fine needle aspiration for the diagnosis of pancreatic cystic neoplasms: a meta-analysis. Pancreatology 2013;13:48-57.
19.
Frossard JL, et al: Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions. Am J Gastroenterol 2003;98:1516-1524.
20.
Maire F, et al: Intraductal papillary mucinous tumors of the pancreas: the preoperative value of cytologic and histopathologic diagnosis. Gastrointest Endosc 2003;58:701-706.
21.
Maire F, et al: Intraductal papillary mucinous neoplasms of the pancreas: performance of pancreatic fluid analysis for positive diagnosis and the prediction of malignancy. Am J Gastroenterol 2008;103:2871-2877.
22.
ASGE Standards of Practice Committee; Muthusamy VR, et al: The role of endoscopy in the diagnosis and treatment of cystic pancreatic neoplasms. Gastrointest Endosc 2016;84:1-9.
23.
Rockacy MJ, et al: Association between KRAS mutation, detected in pancreatic cyst fluid, and long-term outcomes of patients. Clin Gastroenterol Hepatol 2013;11:425-429.
24.
Al-Haddad M, et al: Performance characteristics of molecular (DNA) analysis for the diagnosis of mucinous pancreatic cysts. Gastrointest Endosc 2014;79:79-87.
25.
Hocke M, et al: Pancreatic cystic lesions: the value of contrast-enhanced endoscopic ultrasound to influence the clinical pathway. Endosc Ultrasound 2014;3:123-1230.
26.
Fusaroli P, et al: Contrast harmonic-endoscopic ultrasound is useful to identify neoplastic features of pancreatic cysts (with videos). Pancreas 2016;45:265-268.
27.
Yamashita Y, et al: Usefulness of contrast-enhanced endoscopic sonography for discriminating mural nodules from mucous clots in intraductal papillary mucinous neoplasms: a single-center prospective study. J Ultrasound Med 2013;32:61-68.
28.
Tsujino T, et al: In vivo identification of pancreatic cystic neoplasms with needle-based confocal laser endomicroscopy. Best Pract Res Clin Gastroenterol 2015;29:601-610.
29.
Napoleon B, et al: A novel approach to the diagnosis of pancreatic serous cystadenoma: needle-based confocal laser endomicroscopy. Endoscopy 2015;47:26-32.
30.
Napoleon B, et al: In vivo characterization of pancreatic cystic lesions by needle-based confocal laser endomicroscopy (nCLE): proposition of a comprehensive nCLE classification confirmed by an external retrospective evaluation. Surg Endosc 2016;30:2603-2612.
31.
Kadayifci A, et al: Needle-based confocal laser endomicroscopy for evaluation of cystic neoplasms of the pancreas. Dig Dis Sci 2017;62:1346-1353.
32.
Krishna SG, et al: In vivo and ex vivo confocal endomicroscopy of pancreatic cystic lesions: a prospective study. World J Gastroenterol 2017;23:3338-3348.
33.
Jais B, et al: Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas). Gut 2016;65:305-312.
34.
Nakai Y, et al: Diagnosis of pancreatic cysts: EUS-guided, through-the-needle confocal laser-induced endomicroscopy and cystoscopy trial: DETECT study. Gastrointest Endosc 2015;81:1204-1214.
35.
Wang KX, et al: Assessment of morbidity and mortality associated with EUS-guided FNA: a systematic review. Gastrointest Endosc 2011;73:283-290.
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