Pleural fluid cytological yield and visceral pleural invasion in patients with epithelioid malignant pleural mesothelioma

Our plain-English summary of Pleural fluid cytological yield and visceral pleural invasion in patients with epithelioid malignant pleural mesothelioma, by V. Pinelli, S. Laroumagne, L. Sakr, et al (Journal of Thoracic Oncology, 2012).

The study

• Authors: V. Pinelli, S. Laroumagne, L. Sakr, G.P. Marchetti, G.F. Tassi, P. Astoul
• Journal: Journal of Thoracic Oncology
• Published: 2012;7(3):595-8
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Malignant pleural mesothelioma (MPM) is an aggressive malignancy arising from mesothelial cells lining the pleura. Most commonly, it presents as a unilateral pleural effusion. MPM usually develops on the parietal pleural surface and later spreads to the visceral pleura. Visceral pleural involvement entails a more advanced disease stage and is therefore an important prognostic factor. Pleural fluid (PF) cytology is often the first diagnostic test, but the sensitivity in the literature varies from 4 to 77%. However, no data are available for the diagnostic yield of cytological PF analysis with regard to the visceral pleural involvement. The aim of this study is to assess whether PF cytological yield is related to the extent and pattern of visceral pleural invasion, as assessed by thoracoscopy.

Methods: Medical records of all patients who underwent thoracoscopy for suspicion of malignant pleural effusion from two hospitals were reviewed. Patients were selected if they initially underwent a diagnostic thoracentesis before thoracoscopy, if visceral pleural appearance during thoracoscopy was clearly documented, and MPM confirmed on pleural tissue biopsy.

Results: Seventy-five patients were selected. Forty-five patients had a positive PF cytology on thoracentesis, while 30 had a negative PF cytology. Thoracoscopy showed parietal pleural invasion in all subjects. Interestingly, 82% of patients with positive PF cytology on thoracentesis had visceral pleural involvement, whereas only 30% of those with negative PF cytology had visceral pleural invasion. The pattern of visceral pleural invasion consisted of pleural masses, nodules, or pleural thickening. A multivariate regression identified visceral pleural invasion (p < 0.001) as the only independent factor predicting the positivity of cytology on pleural effusion.

Conclusion: In epithelioid MPM, PF cytological yield was significantly higher in patients with visceral pleural invasion assessed by thoracoscopy. Positive PF cytology is associated with a more advanced disease.

In plain English

This study reviewed the medical records of 103 patients who had thoracoscopy (a camera examination inside the chest) for suspected malignant pleural mesothelioma at two hospitals, in Brescia, Italy, and Marseille, France, between December 2003 and January 2009. Seventy-five patients (51 men and 24 women, aged 43 to 85) met the inclusion criteria. All had the epithelioid type, and all had pleural fluid drawn and examined under the microscope (cytology) before thoracoscopy. The article does not report asbestos exposure. Cytology found cancer in 45 patients and did not in 30. Thoracoscopy showed tumor on the parietal pleura (the chest-wall lining) in all patients. Tumor was also on the visceral pleura (the lung lining) in 82% (37 of 45) of patients with positive cytology and in 30% (9 of 30) of those with negative cytology. In a multivariate analysis, visceral pleural invasion was the only independent factor predicting positive cytology (odds ratio 11.87). The type of lesion seen (masses, nodules, thickening, multiple lesions) was not a predictor. The authors concluded that positive pleural fluid cytology might be associated with more advanced disease.

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: Review of medical records of patients who underwent thoracoscopy at two hospitals
• Who was studied: 75 patients (51 men, 24 women, aged 43 to 85, mean 68) with epithelioid malignant pleural mesothelioma confirmed by biopsy, selected from 103 who had thoracoscopy for suspected mesothelioma in Brescia, Italy, and Marseille, France, December 2003 to January 2009. Sarcomatous, mixed and desmoplastic types were excluded.
• Exposure: Not reported. The article does not discuss asbestos or any other exposure. The factor compared was visceral pleural invasion seen at thoracoscopy.
• Main results:
  • 45 patients had positive pleural fluid cytology (group A) and 30 had negative cytology (group B). Thoracoscopy showed parietal pleural invasion in all 75 patients.
  • Visceral pleural invasion was present in 82% of patients with positive cytology (37 of 45, Table 1) and in 30% of patients with negative cytology (9 of 30).
  • In the multivariate analysis, visceral pleural invasion predicted positive cytology with an odds ratio of 11.87 (p value given as 0.001 in Table 2). The endoscopic lesion types were not independent predictors.
  • Cytology had a diagnostic yield of 80.4% in patients with visceral pleural invasion and 30% in patients without it (the Discussion instead gives 84.1% for the first group).
  • Lesion patterns were 9% masses, 57% nodules, 9% thickening and 25% multiple lesions in the positive-cytology group, and 7% masses, 50% nodules, 20% thickening and 23% multiple lesions in the negative-cytology group.
  • The two cytology groups did not differ significantly in age or gender.
• The authors' conclusion: The authors concluded that cytological yield was significantly higher in patients with visceral pleural invasion, and that positive pleural fluid cytology might therefore be associated with more advanced disease. They also wrote that thoracoscopy should be performed even when cytology is negative.

Topics

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

Medical terms in this study, explained in our Lexicon: Epithelioid, Pleural Mesothelioma, Mesothelial Cells, Pleura, Pleural Effusion, Visceral Pleura, Cytology, Thoracoscopy.

Related studies

• Positive pleural cytology is an indicator for visceral pleural invasion in metastatic pleural effusions — M.E. Froudarakis, J. Plojoux, et al. (2018)
• Diagnostic yield of pleural fluid cytology in malignant effusions: an Australian tertiary centre experience — P. Loveland, M. Christie, et al. (2018)
• Spontaneous bilateral haemothorax as presentation of primary pleural epithelioid haemangioendothelioma — L. Ferreiro, E. San-José, et al. (2017)
• High SUVmax on FDG-PET indicates pleomorphic subtype in epithelioid malignant pleural mesothelioma: supportive evidence to reclassify pleomorphic as nonepithelioid histology — K. Kadota, S.S. Kachala, et al. (2012)
• Usefulness of Claudin 4 in the cytological diagnosis of serosal effusions — S. Lonardi, C. Manera, et al. (2011)
• Impressive clinical response to anti-PD-1 therapy in epithelioid mesothelioma with high clonal PD-L1 expression and EML4-ALK rearrangement — G. Bronte, A. Delmonte, et al. (2020)

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