The diagnosis of desmoplastic malignant mesothelioma and its distinction from fibrous pleurisy: a histologic and immunohistochemical analysis of 31 cases including p53 immunostaining

Our plain-English summary of The diagnosis of desmoplastic malignant mesothelioma and its distinction from fibrous pleurisy: a histologic and immunohistochemical analysis of 31 cases including p53 immunostaining, by W.E. Mangano, P.T. Cagle, A. Churg, et al (American Journal of Clinical Pathology, 1998).

The study

• Authors: W.E. Mangano, P.T. Cagle, A. Churg, R.T. Vollmer, V.L. Roggli
• Journal: American Journal of Clinical Pathology
• Published: 1998;110(2):191-9
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We studied 31 patients with fibrotic pleural lesions and classified them as desmoplastic malignant mesothelioma (DMM) or fibrous pleurisy (FP) using predetermined histologic criteria, including a paucicellular fibrotic pleural lesion with a storiform pattern or the "patternless pattern " of Stout, plus 1 or more of the following: invasion of chest wall or lung, bland necrosis, frankly sarcomatoid areas, and distant metastases. Staining for p53 was performed in 22 cases. Follow-up was obtained on all cases and compared with the histologic diagnoses. For 24 cases, the consensus diagnosis was DMM; 19 of these displayed frankly sarcomatoid areas, 16 showed invasion, and 8, bland necrosis. Of the 24, 23 patients died of disease and 1 was alive with disease. The remaining 7 cases were classified as FP, and all were alive without disease. The concordance among 3 pathologists using the criteria was excellent. Staining for p53 was more common in DMM than in FP, but the difference was not statistically significant. The concordance in interpreting the p53 stains by the same 3 pathologists was moderate. The distinction between DMM and FP in a predominantly fibrotic pleural lesion can be made in most cases with adequate sampling and the use of specific criteria.

In plain English

This pathology study examined 31 patients with scarred (fibrotic) lesions of the pleura. Twenty came from one author's consultation files and 11 from the US/Canadian Mesothelioma Panel, and each had previously been diagnosed as either desmoplastic malignant mesothelioma (DMM) or fibrous pleurisy (FP). Three pathologists reclassified the cases using set criteria: a characteristic fibrous pattern plus at least one of invasion of chest wall or lung, bland necrosis, frankly sarcomatoid areas, or distant metastases. The consensus diagnosis was DMM in 24 cases and FP in 7. Of the 24 DMM patients, 23 died of disease and 1 was alive with disease. All 7 FP patients were alive without disease, a difference the authors reported as highly significant. Agreement among the three pathologists on the diagnosis was rated excellent. Staining for the p53 protein, done in 22 cases, was positive more often in DMM, but the difference was not statistically significant, and agreement in reading the stains was moderate. The authors concluded that the distinction can be made in most cases with adequate sampling and these criteria. The article does not report the patients' 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: Retrospective histologic and immunohistochemical review of previously diagnosed cases, with diagnoses compared against clinical follow-up
• Who was studied: 31 patients with fibrotic pleural lesions previously diagnosed as desmoplastic malignant mesothelioma or fibrous pleurisy. Twenty were from one author's consultation files and 11 from the US/Canadian Mesothelioma Panel. Among the 24 with a consensus diagnosis of DMM there were 19 men and 2 women (sex unknown for 3), with a mean age of 70 years (standard deviation 7). Dates and locations of the patients are not given.
• Exposure: Not reported; the article does not describe asbestos or other exposures of the patients
• Main results:
  • Of the 31 cases, 24 were given a consensus diagnosis of DMM and 7 of FP
  • Of the 24 DMM patients, 23 were dead of disease and 1 was alive with disease. Median follow-up was 6 months (range 8 days to 19 months).
  • All 7 FP patients were alive without disease, with a median follow-up of 20 months (range 6 to 45 months). The outcome difference between DMM and FP was reported as highly significant (P less than .001).
  • Among the 24 DMM cases, frankly sarcomatoid areas were seen in 19, invasion of chest wall or lung in 16, and bland necrosis in 8. No case had distant metastases sampled and available for review.
  • p53 staining was judged positive by a majority of the panelists in 9 of 22 cases. Of the 9 p53-positive cases, 8 were diagnosed as DMM. Of the 13 p53-negative cases, 7 were DMM. Among FP cases, 1 was p53-positive and 6 were p53-negative.
  • The difference in p53 staining between FP and DMM cases was not statistically significant (P greater than .3). In a logistic regression model, p53 staining did not add significant information to the histologic diagnosis for predicting death due to disease (P greater than .5).
  • Agreement among the 3 pathologists on DMM versus FP using histologic criteria alone was described as excellent (agreement statistic 0.73, where 1.0 is perfect). Agreement for p53 staining was 0.48, described as only moderate.
  • In 3 of the 24 consensus DMM cases, 1 observer diagnosed FP. In 2 of the 7 consensus FP cases, 1 observer diagnosed DMM.
• The authors' conclusion: The authors concluded that the distinction between DMM and FP in a predominantly fibrotic pleural lesion can be made in the majority of cases with adequate sampling and use of their specific histologic criteria. They stated that only rarely is a needle biopsy adequate for this distinction, and that pathologists should use extreme caution in diagnosing DMM in 'gray zone' cases that do not fulfill the criteria.

Topics

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

Medical terms in this study, explained in our Lexicon: Desmoplastic Mesothelioma, Malignant Mesothelioma, Pleurisy, Necrosis, Sarcomatoid.

Related studies

• The diagnosis of desmoplastic malignant mesothelioma — T.V. Colby (1998)
• A combination of MTAP and BAP1 immunohistochemistry is effective for distinguishing sarcomatoid mesothelioma from fibrous pleuritis — Y. Kinoshita, M. Hamasaki, et al. (2018)
• The fake fat phenomenon in organizing pleuritis: a source of confusion with desmoplastic malignant mesotheliomas — A. Churg, P. Cagle, et al. (2011)
• 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)
• BAP1 Immunohistochemistry and p16 FISH in the Diagnosis of Sarcomatous and Desmoplastic Mesotheliomas — H.C. Hwang, S. Pyott, et al. (2016)
• Diagnostic usefulness of p16/CDKN2A FISH in distinguishing between sarcomatoid mesothelioma and fibrous pleuritis — D. Wu, K. Hiroshima, et al. (2013)

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