title: Positive pleural cytology is an indicator for visceral pleural invasion in metastatic pleural effusions.
abstract: BACKGROUND
  In case of undiagnosed pleural effusions, it is necessary to conduct thoracentesis with pleural fluid (PF) cytology. Yet, sensitivity of PF cytology is widely variable as a result of sample size, experience, and preparation method.
  
  
  OBJECTIVE
  The aim of this study was to assess whether pleural fluid (PF) cytology is correlated to visceral or parietal pleural invasion as assessed by thoracoscopy in metastatic pleural effusions.
  
  
  METHODS
  All records of patients with pleural effusion were reviewed. The inclusion criteria were as follows: PF cytology, reported appearance of macroscopic pleural invasion during thoracoscopy and malignant diagnosis. Patients with mesothelioma were excluded. Finally, 287 patients who met all criteria were selected. According to the thoracoscopy findings, the extent of the disease on the pleura was analyzed in relation to the PF cytology.
  
  
  RESULTS
  In this study, 160 patients (55.7%) had a positive PF cytology (Group A) while 127 (44.3%) recorded negative PF cytology (Group B). From Group A, patients with visceral pleural invasion were 120 (75%) while only 49 patients (38.5%) were found from Group B and the difference was statistically significant (P < .00001). In univariate analysis, visceral pleural invasion was strongly associated with positive PF cytology (P < .001). Other significant associations with positive PF cytology included PF bloody aspect (P = .012), and endoscopic mixed pattern of pleural invasion (P = .0039). Only visceral pleural invasion was statistically significant in multivariate analysis (P < .001).
  
  
  CONCLUSIONS
  In patients with pleural metastatic disease, visceral pleural invasion is the only significant factor associated with positive pleural fluid cytology.
authors.affiliation: Department of Respiratory Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Marios E
authors.identifier: http://orcid.org/0000-0002-8758-666X
authors.initials: ME
authors.lastname: Froudarakis
authors.affiliation: Department of Thoracic Oncology, Pleural Diseases and Interventional Pulmonology, Hôpital Nord, Aix-Marseille University, Marseille, France.|Division of Pulmonary Medicine, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Jerôme
authors.initials: J
authors.lastname: Plojoux
authors.affiliation: INSERM, GMGF UMRS 910, Aix-Marseille University, Marseille, France.|Hôpital la Timone, Service de Biologie Cellulaire, Marseille, France.
authors.forename: Elise
authors.initials: E
authors.lastname: Kaspi
authors.affiliation: Department of Respiratory Medicine, Medical School, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Stavros
authors.initials: S
authors.lastname: Anevlavis
authors.affiliation: Department of Thoracic Oncology, Pleural Diseases and Interventional Pulmonology, Hôpital Nord, Aix-Marseille University, Marseille, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Laroumagne
authors.affiliation: Department of Pathology, University Hospital of Ioannina, Ioannina, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Karpathiou
authors.affiliation: Department of Thoracic Oncology, Pleural Diseases and Interventional Pulmonology, Hôpital Nord, Aix-Marseille University, Marseille, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Roca
authors.affiliation: Division of Pulmonary Medicine, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Dan
authors.initials: D
authors.lastname: Adler
authors.affiliation: Department of Thoracic Oncology, Pleural Diseases and Interventional Pulmonology, Hôpital Nord, Aix-Marseille University, Marseille, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Dutau
authors.affiliation: Department of Thoracic Oncology, Pleural Diseases and Interventional Pulmonology, Hôpital Nord, Aix-Marseille University, Marseille, France.|Aix-Marseille University, Marseille, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Astoul
mesh_terms: D000368:Aged; D005122:Exudates and Transudates / Q000166:cytology*; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary*; D008297:Male; D008654:Mesothelioma / Q000175:diagnosis / Q000556:secondary*; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D010994:Pleura / Q000473:pathology*; D016066:Pleural Effusion, Malignant / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D010997:Pleural Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D000069258:Thoracentesis / Q000379:methods*; D013906:Thoracoscopy
keywords: cytology; malignant pleural effusion; thoracoscopy