Ultrastructural study of pleural fluid in mesothelioma

Our plain-English summary of Ultrastructural study of pleural fluid in mesothelioma, by M. Legrand, R. Pariente (Thorax, 1974).

The study

• Authors: M. Legrand, R. Pariente
• Journal: Thorax
• Published: 1974;29(2):164-71
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Legrand, M. and Pariente, R. (1974).Thorax, 29, 164-171. Ultrastructural study of pleural fluid in mesothelioma. By means of electron microscopy, three types of malignant cell can be identified in the pleural fluid of patients with pleural mesothelioma. These cell types are described, and the use of cytology in the differential diagnosis of pleural effusion is discussed.

In plain English

This 1974 study from Paris used electron microscopy to examine cells in the pleural fluid (fluid around the lungs) of patients with pleural mesothelioma. Of 32 fluid samples from patients with malignant pleural tumours, the report is based on 22 samples from nine patients judged to have malignant pleural mesothelioma. The article does not discuss asbestos. The authors identified three types of malignant cell. Type 1 cells resembled normal mesothelial cells and carried many microvilli (tiny surface projections). Type 2 cells were elongated with long, winding microvilli, and the authors described them as the most common type. Type 3 cells lacked microvilli and were regarded as undifferentiated. The authors reported that, on repeated examinations, type 1 cells may change into type 2, and type 3 into type 1 or 2. Cells engulfing lymphocytes and damaged phagocytes were seen in fluid from mesothelioma and from secondary pleural tumours. The authors concluded that pleural fluid should be examined repeatedly when a malignant pleural tumour is suspected, cautioning that normal mesothelial cells must be distinguished from malignant ones.

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: Descriptive electron microscopy study of pleural fluid specimens (case series)
• Who was studied: 32 pleural fluid specimens from patients with malignant pleural tumours, examined at the Laboratoire de Cytologie et d'Histologie Pulmonaire, Hôpital Laennec, Paris. The report is based on 22 specimens from 9 patients judged to have malignant pleural mesothelioma. That diagnosis rested on clinical course, spread of the tumour within the pleural cavity, light microscopy, and absence of another primary tumour at necropsy. Study dates are not given.
• Main results:
  • Three types of malignant pleural mesothelioma cell were identified in the pleural fluid.
  • Type 1 cells were mature malignant mesothelial cells with features shared with non-neoplastic mesothelial cells. They were usually numerous, and clumps of them were joined by desmosomes (cell junctions).
  • Type 2 cells were elongated, with numerous, often long and sinuous microvilli. In the Results they were described as scanty, occurring singly or in small groups in the fluid.
  • In the Comment section, the authors stated that type 2 cells were the most common, although type 1 cells most closely resembled normal pleural mesothelial cells.
  • Type 3 cells were rounded and lacked microvilli. They were regarded as undifferentiated malignant pleural cells.
  • Some cells, especially type 2, showed large cytoplasmic vacuoles whose inner wall was fringed with microvilli.
  • Phagocytosis of lymphocytes and damaged phagocytes was seen in fluid from mesothelioma and from pleural secondary growth. The authors described this as unusual in pleural fluid caused by non-neoplastic conditions.
  • According to the authors, repeated examinations showed that type 1 cells may transform into type 2 cells, which they took as showing a common origin.
  • According to the authors, undifferentiated type 3 cells were found on repeated examinations to transform into type 1 or type 2 malignant mesothelial cells.
• The authors' conclusion: The authors concluded that when clinical signs suggest a malignant pleural tumour, the pleural fluid should be examined repeatedly. In their view, finding numerous active phagocytes should prompt a careful search for malignant cells.
• Limitations the authors state:
  • The authors cautioned that, although false positive results are uncommon, normal mesothelial cells must be told apart from malignant mesothelium, and poorly preserved cells should be disregarded.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Thorax, Pleural Mesothelioma, Cytology, Differential Diagnosis, Pleural Effusion.

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• Ultrastructural studies of malignant cells in fluids — G.A. Herrera, J.A. Wilkerson (1985)
• 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)
• Hyaluronic acid in the pleural fluid of patients with malignant pleural mesothelioma — N. Fujimoto, K. Gemba, et al. (2013)
• Comparison of mesothelin and fibulin-3 in pleural fluid and serum as markers in malignant mesothelioma — J. Creaney, I.M. Dick, et al. (2015)

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