'Pseudomesotheliomatous' carcinomas of the pleura: a 10-year analysis of cases from the Environmental Lung Disease Research Group, Cardiff

Our plain-English summary of 'Pseudomesotheliomatous' carcinomas of the pleura: a 10-year analysis of cases from the Environmental Lung Disease Research Group, Cardiff, by R.L. Attanoos, A.R. Gibbs (Histopathology, 2003).

The study

• Authors: R.L. Attanoos, A.R. Gibbs
• Journal: Histopathology
• Published: 2003;43(5):444-52
• Cited by: 63 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims: To undertake a clinicopathological study of diffuse serosal neoplasms of epithelial histogenesis which clinically and pathologically mimic malignant pleural mesothelioma.

Methods And Results: Over a 10-year (1990-2000) study period 53 carcinomas mimicking diffuse pleural mesothelioma ('pseudomesotheliomatous' carcinoma) were identified. The study group comprised 50 men and three females, age range 33-77 (median 68) years. In 46 (87%) cases there was a history of smoking and in 40 (76%) cases a history of asbestos exposure. Histologically the pleural 'pseudomesotheliomatous' carcinomas could be divided into two broad groups: primary pulmonary carcinomas with florid pleurotropic growth (n = 47), of which 34 (70%) were adenocarcinomas; and diffuse carcinomatous involvement of the pleura by metastatic tumour (n = 6). This latter group comprised two transitional cell carcinomas of bladder, one renal (clear) cell carcinoma, one ductal pancreatic adenocarcinoma, one prostatic adenocarcinoma and one squamous cell carcinoma of parotid gland origin. Follow-up data were available in 35 cases. Regardless of tumour type, survival was poor (median 8 months) and comparable to diffuse pleural mesothelioma.

Conclusions: Pleural 'pseudomesotheliomatous' carcinomas are uncommon (comprising 6% of referrals), pathologically heterogeneous tumours with poor prognosis. Tissue diagnosis should be obtained in all cases of suspected diffuse pleural neoplasia. By light microscopy and immunophenotype many of the tumours mimicked malignant mesothelioma. In particular, an awareness that all neoplasms exhibiting squamous differentiation may express cytokeratin 5/6 and thrombomodulin is important to prevent misinterpretation. In this respect, calretinin is regarded as the most specific and sensitive mesothelial marker. Misdiagnosis may have medico-legal implications in asbestos-related compensation claims.

In plain English

The authors reviewed 53 cases from the Environmental Lung Disease Research Group in Cardiff, collected over 1990–2000. In each case a tumour spreading over the pleura looked like diffuse pleural mesothelioma but turned out to be a carcinoma. Two pathologists re-examined tissue from post-mortems and pleural biopsies. The patients were 50 men and three women aged 33 to 77. Forty-seven tumours began in the lung (34 were adenocarcinomas). Six had spread from the bladder, kidney, pancreas, prostate or parotid gland. Most needed special staining to diagnose. None showed calretinin, a mesothelioma marker, though some showed CK5/6 or thrombomodulin. In 10 of 14 cases with no diagnosis before death, the first diagnosis was malignant pleural mesothelioma. Median survival, known for 35 lung-cancer cases, was 8 months. Asbestos exposure was reported in 40 cases (76%). The authors said most cases came from compensation claims, so no meaningful conclusions on asbestos causation could be drawn. They concluded these tumours are uncommon and carry a poor prognosis.

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 clinicopathological case series: two pathologists reviewed tissue sections and clinical records of cases referred to one research group.
• Who was studied: 53 cases of carcinoma that mimicked diffuse pleural mesothelioma, identified over 1990–2000 by the Environmental Lung Disease Research Group, Cardiff, UK. The patients were 50 males and three females aged 33–77 (median 68). 34 cases (65%) were medico-legal referrals. Tissue came from post-mortem material (28), open pleural biopsy (20) and closed pleural biopsy (5).
• Exposure: History of asbestos exposure, including claimed exposure in all 34 medico-legal cases. No fiber types, jobs or doses are reported. Smoking history was also recorded.
• Main results:
  • Of the 53 cases, 46 (87%) had a history of smoking and 40 (76%) had a history of asbestos exposure.
  • Group 1 was 47 primary lung carcinomas with diffuse pleural involvement (45 males, two females; median age 67). Adenocarcinoma made up 34 of these, which is 64% of all 53 cases.
  • Group 2 was six carcinomas that had spread to the pleura from elsewhere in the body.
  • In 14 of the 53 cases (26%) there was no diagnosis before death. In 10 of those 14 (71%), the initial pathological diagnosis was malignant pleural mesothelioma.
  • Immunohistochemistry was needed to confirm the diagnosis in 41 of the 47 group 1 cases (87%), including all adenocarcinomas.
  • Among the 34 lung adenocarcinomas, the markers CEA and Leu-M1 were positive in 27 (79%) and 25 (74%) respectively.
  • The mesothelial marker calretinin was not expressed in any of the 53 carcinomas.
  • CK5/6, another marker associated with mesothelioma, showed focal strong staining in some tumours with squamous features: 2 of the 4 lung squamous cell carcinomas and the one pleomorphic carcinoma with a squamous component.
  • Thrombomodulin, another marker associated with mesothelioma, was expressed in 30% of the 34 lung adenocarcinomas (11 in Table 1).
  • Follow-up data were available for 35 cases, all in group 1 (primary lung carcinomas).
  • Median survival was 8 months. The authors described survival as poor and comparable to diffuse pleural mesothelioma.
• The authors' conclusion: The authors concluded that pleural 'pseudomesotheliomatous' carcinomas are uncommon (6% of referrals) and form a pathologically varied group of tumours with a poor prognosis. They said tissue diagnosis should be obtained in all suspected diffuse pleural tumours. They regarded nuclear calretinin as the most reliable specific marker for mesothelioma, and said CK5/6 and thrombomodulin can be misleading in tumours with squamous differentiation. They noted that misdiagnosis may have medico-legal implications in asbestos-related compensation claims.
• Limitations the authors state:
  • The authors said the study group was selectively biased because most cases came from medico-legal referrals, all of which had a claimed history of asbestos exposure.
  • The authors stated that no meaningful conclusions about asbestos causation could be drawn, given this selection bias and the absence of case-control evidence.

Topics

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

Medical terms in this study, explained in our Lexicon: Carcinoma, Pleura, Neoplasm, Pleural Mesothelioma, Asbestos Exposure, Adenocarcinoma, Squamous Cell Carcinoma, Prognosis.

Related studies

• Expression of calretinin, thrombomodulin, keratin 5, and mesothelin in lung carcinomas of different types: an immunohistochemical analysis of 596 tumors in comparison with epithelioid mesotheliomas of the pleura — M. Miettinen, M. Sarlomo-Rikala (2003)
• Expression of calretinin by breast carcinoma and the potential for misdiagnosis of mesothelioma — G. Powell, H. Roche, et al. (2011)
• Pseudomesotheliomatous carcinoma involving pleura and peritoneum: A clinicopathologic and immunohistochemical study of three cases — I.A. Shah, J.R. Salvatore, et al. (1999)
• GATA3 is a useful immunohistochemical marker for distinguishing sarcomatoid malignant mesothelioma from lung sarcomatoid carcinoma and organizing pleuritis — Z.H. Piao, X.C. Zhou, et al. (2021)
• Pseudomesotheliomatous carcinoma of the pleura: an autopsy case of metastasis from a G-CSF-producing anaplastic carcinoma of the pancreas — Y. Hattori, K. Sentani, et al. (2018)
• Primary thymic epithelial tumours of the pleura mimicking malignant mesothelioma — R.L. Attanoos, F. Galateau-Salle, et al. (2002)

Browse more research in Histopathology, or return to medical research.