Cytopathology of malignant mesothelioma. Reappraisal of the diagnostic value of collagen cores

Our plain-English summary of Cytopathology of malignant mesothelioma. Reappraisal of the diagnostic value of collagen cores, by M. Delahaye, A.A. de Jong, M.A. Versnel, et al (Cytopathology, 1990).

The study

• Authors: M. Delahaye, A.A. de Jong, M.A. Versnel, H.C. Hoogsteden, P. Teeling, T.H. van der Kwast
• Journal: Cytopathology
• Published: 1990;1(3):137-45
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The identification of malignant mesothelial cells in cytological smears prepared from serous effusions is still hampered by the lack of features specific for mesothelial differentiation. We examined the diagnostic value of collagen cores within clusters of tumour cells in cytological smears prepared from effusions from 43 patients with malignant mesothelioma and of 62 cases of metastatic adenocarcinoma. In Giemsa-stained smears collagen cores were detected in 51% of the cases of malignant mesothelioma and in none of the smears with metastatic adenocarcinoma. Using the Azan stain, collagen cores were detected in 64% of the malignant mesotheliomas and 4% of the adenocarcinomas. Immunoelectron microscopy demonstrated that the collagen cores are largely composed of collagen type III fibrils and some elastin embedded in a homogenous extracellular matrix. It can be concluded that the presence of collagen cores within clusters of tumour cells is highly suggestive of mesothelial differentiation and a common finding in malignant mesothelioma.

In plain English

This laboratory study examined whether collagen cores, sharply outlined material inside clusters of tumour cells, help tell malignant mesothelioma apart from metastatic adenocarcinoma in fluid from body cavities. The authors examined pleural effusions from 43 patients with confirmed malignant mesothelioma and fluid from 62 patients with adenocarcinoma that had spread to the pleural or peritoneal cavity. In the mesothelioma group, collagen cores were found in 22 of 43 Giemsa-stained specimens (51%) and in 23 of 36 Azan-stained slides (64%). In the adenocarcinoma group, none of the 62 Giemsa-stained cases showed cores. Azan-stained smears showed cores in three adenocarcinoma cases: one from the breast and two from the ovary. In 11 mesothelioma cases, cores were found only after a thorough search. They could hardly be seen with the Papanicolaou stain. Immunoelectron microscopy showed that most of the fibrils in the cores were collagen type III. The authors concluded that collagen cores in smears containing malignant epithelial cells strongly suggest malignant mesothelioma. They noted that cores may occasionally occur among benign mesothelial cells. Asbestos exposure was not studied.

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: Diagnostic cytology study of fluid smears, with immunoelectron microscopy of the collagen cores
• Who was studied: Pleural effusions from 43 patients (41 males, two females) with malignant mesothelioma confirmed by histology and/or electron microscopy, and serous effusions from 62 patients with adenocarcinoma metastatic to the pleural or peritoneal cavity (27 pleural, 35 peritoneal)
• Exposure: Asbestos exposure was not studied or reported; the study concerned a microscopic feature used in diagnosis
• Main results:
  • Mesothelioma group, Giemsa stain: collagen cores in 22 of 43 specimens (51%)
  • Mesothelioma group, Azan stain: collagen cores in 23 of 36 slides (64%)
  • Adenocarcinoma group, Azan stain: collagen cores in three cases (one breast primary, two ovarian primaries)
  • Adenocarcinoma group, Giemsa stain: no collagen cores in any of the 62 cases
  • Mesothelioma group: in 11 cases, collagen cores were identified only after a thorough search of the slides
  • With the Papanicolaou stain, the cores did not take up the stain and could hardly be seen
  • Cores were also found in mesothelioma smears dominated by morulae or small clusters, not only papillary fragments
  • Immunoelectron microscopy: most collagen fibrils in the cores were collagen type III, with occasional type I fibrils
• The authors' conclusion: The authors concluded that the presence of collagen cores in cytological smears containing malignant epithelial cells strongly suggests a diagnosis of malignant mesothelioma
• Limitations the authors state:
  • Collagen cores may occasionally be found among benign mesothelial cells
  • In 25% of cases, by the authors' account, only a few collagen cores were present, so finding them required a careful search

Topics

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

Medical terms in this study, explained in our Lexicon: Cytology, Mesothelioma, Collagen, Mesothelial Cells, Adenocarcinoma, Fibril.

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