The sensitivity of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma

Our plain-English summary of The sensitivity of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma, by E.A. Rakha, S. Patil, K. Abdulla, et al (Diagnostic Cytopathology, 2010).

The study

• Authors: E.A. Rakha, S. Patil, K. Abdulla, M. Abdulkader, Z. Chaudry, I.N. Soomro
• Journal: Diagnostic Cytopathology
• Published: 2010;38(12):874-9
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pleural malignant mesothelioma (MM), which is an aggressive neoplasm with a high mortality, frequently manifests initially as pleural effusions. The sensitivity of cytologic examination for its diagnosis varies widely in literature and most of the figures are from earlier studies with conventional cytologic preparations. The objective of this study was to provide the current evidence on the role and sensitivity of cytologic examination of pleural fluid in the diagnosis of MM. We reviewed the cytologic findings in pleural effusions of a large series of histologically proven MM (234 cases) diagnosed in our institution between 2001 and 2008. Of all cases, 154 (66%) had cytologic material examined. A specific diagnosis of MM was rendered or suspected in 53% (79 patients). The lowest sensitivity (20%) was noticed in sarcomatoid MM cases. MM was favored over adenocarcinoma in 97% of patients with positive cytologic findings that have been confirmed with immunohistochemistry. In this series, five cases were inadequate and five cases were initially reported as atypical, whereas 65 cases (44%) were reported as negative for malignancy. On review of the cytology slides, only four cases were upgraded from benign to suspicious compared to four cases downgraded from suspicious to atypical but no significant improvement to the diagnosis could be made on revision. These data suggested that a cytologic diagnosis contributed useful information in patients with epithelioid and biphasic pleural MM. Limitations of the cytologic examination of MM should also be acknowledged.

Copyright © 2010 Wiley-Liss, Inc.

In plain English

This study, from the Department of Histopathology at Nottingham City Hospital in the United Kingdom, measured how often examining cells in pleural fluid (fluid around the lungs) detected pleural malignant mesothelioma. The authors reviewed the records of all 234 patients whose pleural mesothelioma was confirmed by biopsy between January 2001 and December 2008. Patients with peritoneal mesothelioma were excluded. Of the 234, 154 had fluid cytology, and two cytopathologists re-examined those slides. The study did not examine asbestos exposure. In the original reports, mesothelioma was diagnosed or suspected in 79 of 154 cases, a sensitivity of 51.3%. After excluding 5 inadequate samples, sensitivity was 53.0%. Sixty-five cases were originally reported as benign. Sensitivity differed by tumor type: 20% for sarcomatoid, 55.4% for epithelioid, and 84.6% for tumors without a specified subtype. Re-examining the slides did not change overall sensitivity. Because every patient had mesothelioma, specificity could not be measured, and the reviewers knew the diagnosis. The authors concluded that cytology was diagnostic or contributory in approximately half of cases with adequate samples.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective single-institution review of how sensitive pleural fluid cytology was in patients with biopsy-confirmed pleural mesothelioma, with blinded re-review of the slides by two cytopathologists
• Who was studied: 234 patients with histologically proven pleural malignant mesothelioma at Nottingham City Hospital, UK, January 2001 to December 2008. Peritoneal mesothelioma was excluded. 196 were male and 38 female, with a median age of 71 years. 154 had cytologic material examined.
• Main results:
  • Of the 234 patients, 154 (66%) had cytologic material examined, and all of it was available for review.
  • Original cytology reports for the 154 cases: 5 (3.2%) inadequate and 65 (42.2%) benign or no evidence of malignancy.
  • Mesothelioma was diagnosed or suspected on cytology in 79 of 154 cases, a sensitivity of 51.3%. Excluding inadequate samples, sensitivity was 53.0%.
  • Sarcomatoid mesothelioma had the lowest sensitivity (20%), and 11 of 15 sarcomatoid cases (73.3%) had a benign cytologic diagnosis.
  • Epithelioid mesothelioma had a sensitivity of 55.4%.
  • Mesothelioma without a specified subtype had the highest sensitivity (84.6%).
  • Among patients with positive cytologic findings confirmed by immunocytochemistry, mesothelioma was favored over adenocarcinoma in 97%.
  • On re-review, 11 cases were moved up from benign (7 to atypical, 4 to suspicious), and 4 suspicious cases were moved down to atypical. Overall sensitivity for the 154 cases did not change after revision.
• The authors' conclusion: The authors concluded that, in routine practice, cytologic examination was diagnostic or contributory to the diagnosis of mesothelioma in approximately half of cases with adequate cytologic preparations. They found sensitivity highest for epithelioid and lowest for sarcomatoid mesothelioma.
• Limitations the authors state:
  • Only patients known to have mesothelioma were included, so false-positive and true-negative results, specificity, and positive predictive value could not be assessed.
  • The reviewing cytopathologists knew that all patients had histologically confirmed mesothelioma.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Neoplasm, Pleural Effusion, Sarcomatoid, Adenocarcinoma, Immunohistochemistry, Cytology, Epithelioid.

Related studies

• The role of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma — A.A. Renshaw, B.R. Dean, et al. (1997)
• Evaluation of seven tumour markers in pleural fluid for the diagnosis of malignant effusions — M. Miédougé, P. Rouzaud, et al. (1999)
• The application of immunocytochemistry to direct smears in the diagnosis of effusions — S.M. Knoepp, J. Placido, et al. (2013)
• Investigating unilateral pleural effusions: the role of cytology — D.T. Arnold, D. De Fonseka, et al. (2018)
• Diagnostic use of muscle markers in the cytologic evaluation of serous fluids — A.M. Afify, B.M. Al-Khafaji, et al. (2002)
• Vascular endothelial growth factor in pleural fluid for differential diagnosis of benign and malignant origin and its clinical applications — A. Fiorelli, G. Vicidomini, et al. (2011)

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