Mesothelioma: a study of 22 gases

Our plain-English summary of Mesothelioma: a study of 22 gases, by J.A. King, J.A. Tucker, S.W. Wong (Southern Medical Journal, 1997).

The study

• Authors: J.A. King, J.A. Tucker, S.W. Wong
• Journal: Southern Medical Journal
• Published: 1997;90(2):199-205
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mesothelioma is a rare, asbestos-associated tumor that infrequently metastasizes. We reviewed 22 autopsies (from February 1989 through July 1994) showing mesothelioma. We determined distribution of metastases and staining characteristics of primary mesotheliomas compared to tissue involved by metastases and/or direct extension. Mean patient age was 68 years (range, 38 to 88 years); black:white patient ratio, 4:18; and male:female patient ratio, 2:1. All patients had a history of asbestos exposure. Fifteen autopsies were complete and 7 were limited to the thoracic cavity. Multiple sites were involved by direct extension. Metastases were in multiple sites, including omentum, stomach, intestine, mesentery, adrenal glands, ovary, pancreas, kidneys, liver, spleen, and vertebrae. Results of immunohistochemical staining of primary mesotheliomas and metastases were similar; both were positive for low-molecular-weight keratin and negative for carcinoembryonic antigen, Leu-M1, Ber-EP4, and periodic acid-Schiff reagent with diastase. Results of testing for high-molecular-weight keratin were variable.

In plain English

This study reviewed autopsies done at the University of South Alabama Medical Center from February 1989 through July 1994. Of 161 autopsies for asbestosis, all requested by families because of a history of asbestos exposure, 22 showed mesothelioma, and these 22 cases were studied. Mean age was 68 years (range 38 to 88). All patients had a clinical history of asbestos exposure, most often from work in shipyards or on ships. The article does not name fiber types. Pleural and/or diaphragmatic plaques were found in 20 of the 22 cases (91%). In 21 cases the tumor encased one lung, and one case was a peritoneal mesothelioma. Seventeen tumors were biphasic and five were epithelial only. Tumor had spread to many sites, including the omentum, stomach, intestine, adrenal glands, ovary, pancreas, kidneys, liver, spleen and vertebrae. One case did not spread beyond the lung and pleura. Primary tumors and metastases stained similarly: positive for low-molecular-weight keratin and negative for carcinoembryonic antigen, Leu-M1 and Ber-EP4. The authors noted that seven autopsies were limited to the chest, so distant metastases could not be documented in those cases.

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: Retrospective review of autopsy cases (case series) of mesothelioma, with immunohistochemical staining of primary tumors and of metastases or areas of direct extension
• Who was studied: 22 cases of mesothelioma found among 161 autopsies for asbestosis at the University of South Alabama Medical Center, Mobile, Alabama, February 1989 through July 1994. All autopsies were requested by families because of a history of asbestos exposure. 15 autopsies were complete and 7 were limited to the thoracic cavity. Mean age 68 years (range 38 to 88); black:white ratio 4:18.
• Exposure: Asbestos exposure by clinical history; fiber types not reported. Most patients were exposed while working in shipyards or on ships, in jobs including pipe fitter, boilermaker, carpenter, welder, plumber, tacker, shipfitter, electrician and longshoreman. Other listed occupations were machinist, factory worker, industrial welding and miner. In the 13 cases where duration was known, 85% were exposed for 20 or more years. Of the 13 cases with smoking history available, 11 (85%) were smokers.
• Main results:
  • Pleural and/or diaphragmatic plaques were present in 20 of the 22 cases (91%).
  • Half of the cases (11) had mild interstitial fibrosis. Ferruginous bodies were seen on hematoxylin-eosin-stained sections in 7 cases (32%).
  • After lung tissue digestion, 81% (17 of 21 cases) had more than 10 ferruginous bodies per slide; two cases had no ferruginous bodies after digestion (no lung tissue was available for digestion in one case).
  • The mesotheliomas encased the right lung in 10 cases and the left lung in 11 cases; one case was a peritoneal mesothelioma.
  • 17 mesotheliomas (77%) were biphasic and 5 (23%) had only an epithelial pattern.
  • Metastases and/or direct extension involved multiple sites, including omentum, stomach, intestine, mesentery, adrenal glands, ovary, pancreas, kidneys, liver, spleen and vertebrae. One case (Case 22) involved only the lung and pleura with no metastases or direct extension.
  • Immunohistochemical staining of primary mesotheliomas and of metastases gave similar results: both were positive for low-molecular-weight keratin and negative for carcinoembryonic antigen (CEA), Leu-M1 and Ber-EP4. Results for high-molecular-weight keratin were variable. Occasional areas of necrosis were falsely positive for CEA.
  • None of the 22 primary mesotheliomas and none of the 20 metastases reacted positively to periodic acid-Schiff (PAS) with diastase.
  • Alcian blue staining was highly variable. 5 of 21 primary mesotheliomas and 4 of 20 metastases stained positively with alcian blue; none stained positively after hyaluronidase.
• The authors' conclusion: The authors stated that primary mesotheliomas and their metastases or areas of direct extension stained similarly, being negative for CEA, Leu-M1, Ber-EP4 and PAS with diastase and positive for low-molecular-weight keratin. They noted that mesothelioma can involve multiple sites, so areas of metastasis or direct extension may be biopsied instead of the pleura.
• Limitations the authors state:
  • Family members could not supply complete, detailed occupational exposure histories in all cases.
  • In 7 cases the autopsy was limited to the thoracic cavity, so distant metastases in those cases could not be documented.
  • Areas involved by direct extension are sometimes difficult to distinguish from true metastases.
  • It was not known how long each tissue specimen had been in formalin, which the authors gave as a reason why alcian blue staining was not consistent.

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, Metastasis, Asbestos Exposure, Omentum, Mesentery, Immunohistochemistry, Carcinoembryonic Antigen (CEA), Ber-EP4.

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