Solitary (localized) fibrous mesothelioma: evidence against mesothelial cell origin

Our plain-English summary of Solitary (localized) fibrous mesothelioma: evidence against mesothelial cell origin, by P.A. Dervan, B. Tobin, M. O'Connor (Histopathology, 1986).

The study

• Authors: P.A. Dervan, B. Tobin, M. O'Connor
• Journal: Histopathology
• Published: 1986;10(8):867-75
• Cited by: 123 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Five cases of solitary (localized) fibrous mesothelioma were studied immunohistochemically, utilizing monoclonal antibodies against high and low molecular weight cytokeratin, vimentin, carcinoembryonic antigen, epithelial membrane antigen and factor VIII related antigen. In contrast to normal mesothelium and contrary to previous reports from malignant mesotheliomas all the tumours were negative for keratin. They were strongly positive for vimentin. Two cases were studied electron microscopically; no ultrastructural evidence of mesothelial cell differentiation was identified. Our immunohistochemical and ultrastructural findings argue against a mesothelial cell origin, whereas the presence of vimentin suggests a mesenchymal histogenesis. It is postulated that these tumours arise from sub-mesothelial mesenchymal connective tissue.

In plain English

This laboratory study, from a hospital pathology department in Dublin, Ireland, examined tumours from five patients with solitary (localized) fibrous mesothelioma. The authors stained the tumours for markers that distinguish mesothelial and epithelial cells from connective-tissue cells, and examined two tumours under an electron microscope. All five tumours were negative for cytokeratin, a marker found in normal mesothelium. Virtually all tumour cells stained intensely for vimentin, a marker of connective-tissue cells. Staining for epithelial membrane antigen, carcinoembryonic antigen and factor VIII related antigen was negative. Under the electron microscope, the tumour cells lacked the long slender microvilli typical of mesothelial cells. In every tumour, a layer of mesothelial cells lay over the tumour, separated from it by a fibrous band. The two patients asked specifically reported no asbestos exposure, and no ferruginous bodies were seen in lung tissue from four patients. In their introduction, the authors stated that this tumour is not related to asbestos exposure. The authors concluded that their findings gave no evidence that these tumours come from mesothelial cells, and that they probably arise from the connective tissue beneath the mesothelium.

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: Case series of five tumours studied by microscopy, immunohistochemical staining and, in two tumours, electron microscopy
• Who was studied: Five patients with solitary (localized) fibrous mesothelioma, aged 32 to 75 (four men, one woman), from the Department of Pathology, Mater Misericordiae Hospital, Dublin, Ireland; study dates not given
• Exposure: Asbestos exposure was not the subject of the study. The two patients questioned specifically reported no asbestos exposure, and no ferruginous bodies were seen in lung tissue from four patients. In their introduction, the authors stated that this tumour is not related to asbestos exposure.
• Main results:
  • All five tumours were negative for cytokeratin
  • In all five cases, virtually all tumour cells stained intensely for vimentin
  • Staining for epithelial membrane antigen, carcinoembryonic antigen and factor VIII related antigen was negative in the tumours
  • In the two tumours examined by electron microscopy, the small cell-surface projections did not resemble the long slender microvilli characteristic of mesothelial cells
  • All tumours had a layer of enlarged mesothelial cells lying over them, separated from the tumour by a fibrous band
  • No history of asbestos exposure was found in the two patients questioned specifically, and no ferruginous bodies were seen in lung tissue from four patients
  • Four tumours were surgically removed. One patient (case 2) died of a cardiac arrhythmia after the operation; case 4 died of a pulmonary embolus; case 5 was found at autopsy. The tumours measured 3 to 25 cm.
• The authors' conclusion: The authors concluded that their histological, electron-microscopic and staining findings gave no evidence that these tumours are derived from mesothelial cells. They believed the tumours most probably arise from mesenchymal (connective) tissue beneath the mesothelium.

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, Mesothelial Cells, Monoclonal, Carcinoembryonic Antigen (CEA), Epithelial Membrane Antigen (EMA), Mesothelium, Malignant Mesothelioma.

Related studies

• Immunohistochemical evidence of the mesothelial histogenesis of a uterine adenomatoid tumor — Y. Satoh, M. Hiraguchi, et al. (1998)
• Immunoperoxidase localization of keratin proteins, carcinoembryonic antigen, and factor VIII in adenomatoid tumors: evidence for a mesothelial derivation — J.W. Said, G. Nash, et al. (1982)
• Localized fibrous tumor of the serosal cavities. Immunohistochemical, electron-microscopic, and flow-cytometric DNA study — A.K. el-Naggar, J.Y. Ro, et al. (1989)
• Localized malignant mesothelioma, an unusual and poorly characterized neoplasm of serosal origin: best current evidence from the literature and the International Mesothelioma Panel — A.M. Marchevsky, A. Khoor, et al. (2020)
• Intrapulmonary localized fibrous tumor. Intraparenchymal so-called localized fibrous mesothelioma — S.A. Yousem, S.D. Flynn (1988)
• Solitary fibrous tumor of the mediastinum — N. Weidner (1991)

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