Sarcomatoid Mesothelioma: A Clinicopathological and Immunohistochemical Study of 64 Cases

Our plain-English summary of Sarcomatoid Mesothelioma: A Clinicopathological and Immunohistochemical Study of 64 Cases, by D.M. Oramas, M. Zaleski, C.A. Moran (International Journal of Surgical Pathology, 2021).

The study

• Authors: D.M. Oramas, M. Zaleski, C.A. Moran
• Journal: International Journal of Surgical Pathology
• Published: 2021;29(8):820-825
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Sixty-four cases of sarcomatoid pleural mesothelioma represent the basis of this study. The patients are 51 men and 13 women between the ages of 42 and 79 years, who presented with symptoms of chest pain, cough, and weight loss. Diagnostic imaging showed the presence of diffuse pleural thickening with encasement of the lung parenchyma in all the cases. All patients had surgical resection via extrapleural pneumonectomy. By immunohistochemistry, all cases were positive for cytokeratin AE1/AE3; however, reactivity with other markers including keratin 5/6, calretinin, and D2-40 was seen in different proportions, whereas a few cases showed positive staining for GATA3, WT1, and p40. All tumors were negative for carcinomatous epitopes (carcinoembryonic antigen, CD15, and TTF1). Our findings show that even though the use of immunohistochemical stains plays an important role in the final interpretation, the best results are accomplished by a global interpretation of clinical, radiographical, and immunohistochemical findings. It is also important to highlight that it does not seem to be a single immunohistochemical stain that is pathognomonic of sarcomatoid mesothelioma and that some other stains that are commonly used for other tumors may also show positive staining in a small percentage of sarcomatoid mesotheliomas.

In plain English

This study described 64 patients with sarcomatoid pleural mesothelioma, a spindle-cell form of mesothelioma of the lining around the lung. All had their tumors removed by extrapleural pneumonectomy between 1996 and 2015. They were 51 men and 13 women aged 42 to 79 (average 60.5). The article does not report asbestos exposure. The authors stained the tumors with a panel of laboratory markers. Cytokeratin AE1/AE3 was positive in all 64 cases, calretinin in 52, pan-cytokeratin in 51, WT1 in 48, D2-40 in 33, keratin 5/6 in 14, GATA3 in 10 and p40 in 4. CEA, TTF1, CD15 and PAX8 were negative in every case. The authors noted that their GATA3 rate (15.6%) was far below rates reported by others. All 64 patients died of the disease. Survival, measured from surgery to death, averaged 1 year (range 0.5 to 3 years). Survival did not differ significantly by age over or under 60, and no marker was associated with outcome. The authors concluded that no single stain appears to identify sarcomatoid mesothelioma on its own.

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 and immunohistochemical case series of surgically resected tumors, with review of slides and medical records
• Who was studied: 64 patients with sarcomatoid pleural mesothelioma (51 men, 13 women, aged 42 to 79, average 60.5 years), all treated by extrapleural pneumonectomy between 1996 and 2015
• Main results:
  • Cytokeratin AE1/AE3 was positive in all 64 tumors, with strong cytoplasmic staining
  • Pan-cytokeratin was positive in 51 of 64 cases
  • Keratin 5/6 was positive in 14 of 64 cases
  • WT1 was positive in 48 of 64 cases
  • Calretinin was positive in 52 of 64 cases and D2-40 in 33 of 64 cases
  • GATA3 was positive in 10 of 64 cases and p40 in 4 of 64 cases
  • CEA, TTF1 and CD15 were negative in all tumors
  • PAX8 was negative in all 64 cases
  • The GATA3 positivity rate in this cohort (15.6%) was, the authors noted, far below that reported by others
  • About 40% of tumors also contained a small epithelioid component (less than 10% of the tumor)
  • Survival was measured from the date of surgery to the date of death
  • All 64 patients died of disease. Average and most common survival time from surgery was 1 year, with a range of 0.5 to 3 years
  • No significant survival difference was found between patients over and under 60, and no immunohistochemical marker was associated with outcome
• The authors' conclusion: The authors concluded that a panel of immunohistochemical stains is appropriate, but that no single stain appears to identify sarcomatoid mesothelioma on its own. Stains used for other tumors (such as GATA3 and p40) can be positive in a small percentage of cases. The best assessment rests on a global interpretation of clinical, radiological, immunohistochemical and, when available, molecular findings.

Topics

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

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Mesothelioma, Pleural Mesothelioma, Diffuse Pleural Thickening, Parenchyma, Surgical Resection, Extrapleural Pneumonectomy (EPP), Immunohistochemistry.

Related studies

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• Observations on bronchiolo-alveolar carcinomas with special emphasis on localized lesions. A clinicopathological, ultrastructural, and immunohistochemical study of 11 cases — C.A. Axiotis, T.A. Jennings (1988)
• Synovial sarcoma of the pleura and its differentiation from other primary pleural tumours: a clinicopathological and immunohistochemical review of three cases — A.G. Nicholson, P. Goldstraw, et al. (1998)
• An immunohistochemical comparison of two TTF-1 monoclonal antibodies in atypical squamous lesions and sarcomatoid carcinoma of the lung, and pleural malignant mesothelioma — S. Klebe, A. Swalling, et al. (2016)
• MUC4, a novel immunohistochemical marker identified by gene expression profiling, differentiates pleural sarcomatoid mesothelioma from lung sarcomatoid carcinoma — V.J. Amatya, K. Kushitani, et al. (2017)
• 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)

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