title: 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.
abstract: The differential diagnosis of solitary pancreatic cystic lesions is sometimes difficult. Needle-based confocal laser endomicroscopy (nCLE) performed during endoscopic ultrasound-fine-needle aspiration (EUS-FNA) enables real-time imaging of the internal structure of such cysts. Criteria have already been described for serous cystadenoma and intraductal papillary mucinous neoplasm (IPMN). The aims of the study were to determine new nCLE criteria for the diagnosis of pancreatic cystic lesions, to propose a comprehensive nCLE classification for the characterization of those lesions, and to carry out a first external retrospective validation .
  
  
  
  Thirty-three patients with a lone pancreatic cystic lesion were included (CONTACT 1 study). EUS-FNA was combined with nCLE. Diagnosis was based on either pathology result (Group 1, n = 20) or an adjudication committee consensus (Group 2, n = 13). Six investigators, unblinded, studied cases from Group 1 and identified nCLE criteria for mucinous cystic neoplasm (MCN), pseudocyst (PC), and cystic neuroendocrine neoplasm (NEN). Four external reviewers assessed, blinded, the yield and interobserver agreement for the newly identified (MCN, PC) and previously described (IPMN, SC) criteria in a subset of 31 cases.
  
  
  
  New nCLE criteria were described for MCN (thick gray line), PC (field of bright particles), and cystic NEN (black neoplastic cells clusters with white fibrous areas). These criteria correlated with the histological features of the corresponding lesions. In the retrospective validation, a conclusive nCLE result was obtained for 74 % of the cases (87 % "true" and 13 % "false" with respect to the final diagnosis). On this limited case series, the nCLE criteria showed a trend for high diagnostic specificity (>90 % for mucinous cysts, 100 % for non-mucinous cysts).
  
  
  
  Based on this newly completed atlas of interpretation criteria, nCLE could facilitate the diagnosis of pancreatic cystic lesion types.
authors.affiliation: Department of Gastroenterology, Hôpital Privé Jean Mermoz, Générale de Santé, 4 rue Jacqueline Auriol, 69008, Lyon, France. bertrand.napoleon@dartybox.com.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Napoleon
authors.affiliation: Department of Biopathology, Centre Léon Bérard, Lyon, France.
authors.forename: Anne-Isabelle
authors.initials: AI
authors.lastname: Lemaistre
authors.affiliation: Department of Gastroenterology, Hôpital Privé Jean Mermoz, Générale de Santé, 4 rue Jacqueline Auriol, 69008, Lyon, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Pujol
authors.affiliation: Department of Hepato-gastroenterology, Institut Paoli Calmettes, Marseille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Caillol
authors.affiliation: Medico-surgical Department of Hepato-gastroenterology, Hôpital Saint-Philibert, Lomme-lès-Lille, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Lucidarme
authors.affiliation: Department of Digestive Surgery, Hôpital Privé Jean Mermoz, Générale de Santé, Lyon, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Bourdariat
authors.affiliation: Department of Biopathology, Centre Léon Bérard, Lyon, France.
authors.forename: Blandine
authors.initials: B
authors.lastname: Morellon-Mialhe
authors.affiliation: Department of Gastroenterology, Hôpital Privé Jean Mermoz, Générale de Santé, 4 rue Jacqueline Auriol, 69008, Lyon, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Fumex
authors.affiliation: Department of Gastroenterology, Hôpital Privé Jean Mermoz, Générale de Santé, 4 rue Jacqueline Auriol, 69008, Lyon, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Lefort
authors.affiliation: Department of Gastroenterology, Hôpital Privé Jean Mermoz, Générale de Santé, 4 rue Jacqueline Auriol, 69008, Lyon, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lepilliez
authors.affiliation: Department of Gastroenterology, Clinique du Trocadéro, Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Palazzo
authors.affiliation: Department of Biopathology, Institut Paoli Calmettes, Marseille, France.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Monges
authors.affiliation: Department of Biopathology, Institut Paoli Calmettes, Marseille, France.
authors.forename: Flora
authors.initials: F
authors.lastname: Poizat
authors.affiliation: Department of Hepato-gastroenterology, Institut Paoli Calmettes, Marseille, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Giovannini
mesh_terms: D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: EUS-FNA; Needle-based confocal laser endomicroscopy; Pancreatic cysts