Electron microscopy remains the gold standard for the diagnosis of epithelial malignant mesothelioma: a case study

Our plain-English summary of Electron microscopy remains the gold standard for the diagnosis of epithelial malignant mesothelioma: a case study, by E.A. Oczypok, T.D. Oury (Ultrastructural Pathology, 2015).

The study

• Authors: E.A. Oczypok, T.D. Oury
• Journal: Ultrastructural Pathology
• Published: 2015;39(2):153-8
• Type of article: Case report
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

This is a case of idiopathic epithelial malignant mesothelioma in a 47-year-old mechanic. The advent of a large battery of immunochemical markers has provided new tools for the diagnosis of mesothelioma in recent years; however, immunostaining can often be misleading or inconsistent, as demonstrated in this case. This report highlights the lasting utility of electron microscopy in the diagnosis of mesothelioma. Ultrastructural features of epithelial mesothelioma were discernable using electron microscopy even on somewhat poorly preserved chest wall biopsy specimens from paraffin blocks. These images, combined with immunostains and a fiber analysis from the lungs, allowed for a final diagnosis of a non-asbestos-related malignant epithelial mesothelioma in this patient.

In plain English

This case report described a 47-year-old man who had worked as a mechanic for over 30 years, including on brakes. The case reached the authors through a medical–legal consultation. Before his death, a lymph node biopsy showed a metastatic epithelial tumor, and a liver biopsy was reported as metastatic, poorly differentiated mesothelioma. He died three weeks after being admitted to hospital. At autopsy a tumor was found in the right kidney. Stains were not typical of mesothelioma, and the kidney tumor and clear tumor cells suggested possible renal cell carcinoma (a kidney cancer). Electron microscopy of a poorly preserved chest wall biopsy showed enough features for the authors to identify the cancer as an epithelioid mesothelioma rather than renal cell carcinoma. Lung tissue contained between two and six asbestos bodies per gram and 682 tremolite cleavage fragments per gram (wet weight). The authors placed these levels in the range seen in people without known asbestos exposure. No pleural plaques were seen. The authors concluded that the findings supported a final diagnosis of non-asbestos-related epithelial malignant mesothelioma.

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 report of a single patient (hospital records, autopsy, staining, electron microscopy and lung fiber analysis); the case came to the authors as part of a medical–legal consultation
• Who was studied: one 47-year-old Caucasian man with no prior medical conditions; the hospital and dates of illness are not stated
• Exposure: work as a mechanic for over 30 years, including work on brakes
• Main results:
  • A left retroperitoneal lymph node biopsy taken before death showed a metastatic, poorly differentiated epithelial tumor (neoplasm)
  • A liver nodule biopsy taken before death was reported as metastatic, poorly differentiated mesothelioma
  • The patient died three weeks after his initial hospital admission
  • At autopsy a tumor was found in the upper pole of the right kidney
  • The combined staining (immunostain) results on biopsy and autopsy tissue were not typical of mesothelioma
  • The kidney tumor found at autopsy and the clear cells with enlarged nuclei seen in multiple tumor samples suggested a possible diagnosis of renal cell carcinoma
  • Electron microscopy of the chest wall biopsy showed areas with numerous elongated microvilli and enlarged desmosomes
  • The authors judged these features sufficient to identify the cancer as an epithelioid mesothelioma and not renal cell carcinoma
  • No pleural plaques were seen at autopsy
  • Lung tissue contained between two and six asbestos bodies per gram of wet tissue
  • The authors placed the asbestos body level in the range seen in controls not exposed to asbestos
  • The 10 uncoated fibers counted were two talc fibers, two silica-only fibers, three titanium fibers, one glass fiber and two tremolite cleavage fragments
  • This corresponded to 682 tremolite cleavage fragments per gram of wet lung tissue
  • The authors placed the tremolite cleavage fragment level in the range seen in control populations with no known asbestos exposure
• The authors' conclusion: The authors concluded that electron microscopy images, together with staining and the lung fiber analysis, allowed a final diagnosis of non-asbestos-related malignant epithelial mesothelioma in this patient
• Limitations the authors state:
  • The tissue used for electron microscopy had been embedded in paraffin, so the cell structure was poorly preserved
  • Examination of autopsy tumor tissue was hindered by post-mortem decay (autolytic changes)
  • Slides from the stains done at the original diagnosing hospital were not obtained for re-interpretation

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Idiopathic, Mesothelioma, Biopsy, Paraffin Block.

Related studies

• An electron microscopy study of the effect of asbestos dust on the lung — J.M. Davis (1963)
• Electron microscopy: a brief history and review of current clinical application — R.E. Gordon (2014)
• The use of a new static device based on the collection of the thoracic fraction for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy — E. Kauffer, J.C. Vigneron, et al. (1996)
• The utility of electron microscopy in detecting asbestos fibers and particles in BALF in diffuse lung diseases — T. Kido, Y. Morimoto, et al. (2017)
• High-resolution electron microscopy of interlysosomal junctions — D. Beju (1988)
• Performance of asbestos fibre counting laboratories by transmission electron microscopy — B. Préat (2001)

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