Electron microscopy in the cytological examination of metastatic pleural effusions

Our plain-English summary of Electron microscopy in the cytological examination of metastatic pleural effusions, by M. Legrand, R. Pariente (Thorax, 1976).

The study

• Authors: M. Legrand, R. Pariente
• Journal: Thorax
• Published: 1976;31(4):443-9
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

In a previous publication the ultrastructure of pleural effusions in cases of pleural mesothelioma was reported. The same method has now been applied to a study of effusions produced by pleural metastases. The findings are considered sufficiently conclusive to justify the use of electron microscopic cytology in determining the nature and sometimes the origin of such effusions.

In plain English

Authors at a hospital in Clamart, France, used electron microscopy to examine cells in pleural effusions (fluid collecting around the lungs) from patients whose cancer had spread to the pleura from elsewhere. They examined 63 pleural fluid samples, using a method they had earlier applied to fluid from patients with pleural mesothelioma. The article does not say how many samples came from each cancer type, and it does not discuss asbestos. The authors described cells from breast, gastrointestinal and pancreatic cancers, among others. Cells from so-called papillary tumours could be confused with mesothelial cells, but their internal structure differed. Some samples held cancer cells whose origin could not be determined. The authors concluded that two features were specific enough to be of great importance in diagnosis: short, straight microvilli (tiny finger-like projections on the cell surface), and one cell enclosed inside another. They judged the method justified for determining the nature, and sometimes the origin, of such effusions. They noted that errors can arise, including between papillary tumours and mesotheliomas.

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 laboratory study: electron microscopic examination of pleural fluid samples, using the authors' previously described technique
• Who was studied: 63 pleural fluid samples from patients with metastatic pleural involvement. The authors were based at Hôpital Antoine Béclère, Clamart, France. The article does not give dates, patient details, or the number of samples per primary cancer type.
• Exposure: Not applicable. The article does not mention asbestos or any occupational exposure. It describes cancer cells in pleural fluid from metastases of breast, gastrointestinal, pancreatic and other tumours.
• Main results:
  • Many tumour cell types were seen, but all shared common features regardless of how differentiated they were.
  • In effusions from breast carcinoma, cells were single or in clusters joined by numerous desmosomes, and lipid inclusions were especially characteristic.
  • Effusions associated with gastrointestinal tumours showed mainly groups of cells that were fragments of tissue. Single cells were uncommon.
  • In effusions from pancreatic tumour metastases, no secretory granules were observed.
  • Cells from tumours of the papillary type could be confused with mesothelial cells because they had mesothelial-type microvilli. Their cytoplasm differed, and these features suggested glandular tumours of ovarian or thyroid origin.
  • Some pleural fluids contained malignant cells of undetermined origin. Their metastatic nature could be assumed when enclosed cells and rough ergastoplasm were present.
• The authors' conclusion: The authors concluded that two features of secondary cancer cells were specific enough to be of great importance in diagnosis: short, straight microvilli and the enclosure of cells. They considered the findings sufficiently conclusive to justify electron microscopic cytology for determining the nature, and sometimes the origin, of metastatic pleural effusions.
• Limitations the authors state:
  • Errors can arise. Macrophages may be confused with mesothelial cells, particularly in chronic effusions.
  • Errors are possible between so-called papillary tumours and mesotheliomas.
  • The authors advised repeating the examination in doubtful cases.

Topics

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

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

Related studies

• The value of anti-calretinin antibody in the differential diagnosis of normal and reactive mesothelia versus metastatic tumors in effusion cytology — H. Nagel, B. Hemmerlein, et al. (1998)
• Cytomorphological features of metastatic squamous cell carcinoma in serous effusions — C.C. Huang, C.W. Michael (2014)
• "Cannonballs" and psammoma bodies: unusual cytologic features of metastatic pulmonary small-cell carcinoma in a pleural effusion — A.B. Conway, M.K. Hart, et al. (2013)
• Accuracy and reproducibility of pleural effusion cytology — A. Fassina, U. Fedeli, et al. (2008)
• Calretinin. A selective marker of normal and neoplastic mesothelial cells in serous effusions — M.C. Barberis, M. Faleri, et al. (1997)
• Usefulness of Claudin 4 in the cytological diagnosis of serosal effusions — S. Lonardi, C. Manera, et al. (2011)

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