'Pleural' and pulmonary carcinosarcomas

Our plain-English summary of 'Pleural' and pulmonary carcinosarcomas, by F.G. Mayall, A.R. Gibbs (The Journal of Pathology, 1992).

The study

• Authors: F.G. Mayall, A.R. Gibbs
• Journal: The Journal of Pathology
• Published: 1992;167(3):305-11
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The histological distinction between carcinosarcoma and mesothelioma has received little attention. The object of this study was to describe the histology and immunohistochemistry of two carcinosarcomas presenting as pleural tumours. These were compared with 12 carcinosarcomas from sites within the lung, and with the established features of mesothelioma. Histologically and immunohistochemically, these 'pleural' carcinosarcomas are similar to conventional pulmonary carcinosarcomas but accurate recognition is hindered by their gross appearance and biphasic histology which closely mimic mesothelioma. They may exhibit features such as neutral mucin, expression of carcinoembryonic antigen, squamous differentiation, and neuroendocrine differentiation which, when present, are evidence against mesothelioma. These tumours are rare and have passed unnoticed until now.

In plain English

This Welsh pathology study described two carcinosarcomas (cancers mixing carcinoma and sarcoma tissue) that presented as tumours of the pleura, the lining around the lungs. The authors compared them with 12 carcinosarcomas inside the lung, all 14 taken from surgical and post-mortem material in their department, and with the known features of mesothelioma. The two pleural tumours had originally been misdiagnosed as mesotheliomas. One encased the lung in a manner typical of mesothelioma. Both patients had a putative history of asbestos exposure, but electron microscope fibre counts were within normal limits. The first patient had heavy industrial nickel exposure, which the authors thought, together with smoking, likely played a part. The first tumour showed squamous differentiation, neutral mucin and carcinoembryonic antigen (CEA). The second showed neuroendocrine differentiation. The authors concluded that 'pleural' carcinosarcoma should be considered when diagnosing mesothelioma, and that these features, when present, are evidence against mesothelioma. They noted that normal fibre counts are not absolute evidence, because mesothelioma can occur without asbestos exposure.

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: Descriptive histopathology and immunohistochemistry study (case series) of 14 carcinosarcomas, focused on two that presented as pleural tumours, compared with 12 lung carcinosarcomas and with published features of mesothelioma
• Who was studied: 14 patients with carcinosarcoma from surgical and post-mortem material examined in the authors' department (Llandough Hospital, Penarth, and University of Wales College of Medicine, Cardiff, UK). Two tumours were predominantly pleural (cases 1 and 2) and 12 were within the lung. The study dates are not stated.
• Exposure: Exposure was not the main subject. The two pleural cases had a putative history of asbestos exposure, with no fibre type named. Lung fibre counts by transmission electron microscopy were within the normal range in both. Case 1 also had heavy industrial nickel exposure. Asbestos fibre counts were not done on the other 12 cases.
• Main results:
  • Both pleural tumours had originally been misdiagnosed as mesotheliomas.
  • Case 1 had a large, mainly pleural tumour that encased the lung in a manner typical of mesothelioma. For neither pleural tumour could a site of origin within the lung tissue be identified.
  • In both pleural cases, electron microscopic mineral fibre counts were within normal limits.
  • In case 1, the epithelial part of the tumour was classified as adenosquamous, with small collections of neutral mucin and with keratin pearls (squamous differentiation).
  • In case 2, the epithelial part resembled small cell carcinoma. Staining for bombesin indicated neuroendocrine differentiation, and the tumour was positive for NSE but not for chromogranin or CEA.
  • CEA, a marker the authors describe as extremely rare in mesothelioma, was found in case 1 and in all but one of the other carcinosarcomas in the study.
  • Staining for desmin was negative in all tumours in the study.
  • Both pleural tumours occurred in elderly people with a history of heavy smoking. The authors considered that case 1's heavy industrial nickel exposure, together with smoking, was likely to have played a part in the tumour.
• The authors' conclusion: The authors concluded that 'pleural' carcinosarcoma should be considered in the differential diagnosis of mesothelioma. They also concluded that neutral mucin, CEA positivity, squamous differentiation and neuroendocrine differentiation, when present, are evidence against mesothelioma.
• Limitations the authors state:
  • The authors note that normal fibre counts support the diagnosis but are not absolute evidence, because mesotheliomas can occur without asbestos exposure.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Histology, Immunohistochemistry, Biphasic Mesothelioma, Carcinoembryonic Antigen (CEA).

Related studies

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• Carcinosarcoma of the spermatic cord — M. Nistal, F. Burgos, et al. (1990)
• Sarcomatoid carcinoma (carcinosarcoma) of the lung mimics malignant pleural mesothelioma on 18F-FDG PET/CT: a report of 2 cases — A. Ciarallo, W. Makis, et al. (2012)
• High SUVmax on FDG-PET indicates pleomorphic subtype in epithelioid malignant pleural mesothelioma: supportive evidence to reclassify pleomorphic as nonepithelioid histology — K. Kadota, S.S. Kachala, et al. (2012)
• An attempt to use the WHO typing in the histological classification of lung carcinomas — A. Reinilä, K. Dammert (1974)
• Effectiveness of Nivolumab on Sarcomatoid Malignant Pleural Mesothelioma With Eosinophilia and Eosinophilic Pleural Effusion — M. Yamazoe, H. Ozasa, et al. (2019)

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