Myxoid variant epithelioid pleural mesothelioma defines a favourable prognosis group: an analysis of 191 patients with pleural malignant mesothelioma

Our plain-English summary of Myxoid variant epithelioid pleural mesothelioma defines a favourable prognosis group: an analysis of 191 patients with pleural malignant mesothelioma, by F.S. Alchami, R.L. Attanoos, A.R. Bamber (Journal of Clinical Pathology, 2017).

The study

• Authors: F.S. Alchami, R.L. Attanoos, A.R. Bamber
• Journal: Journal of Clinical Pathology
• Published: 2017;70(2):179-182
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma shows marked cytoarchitectural diversity. The aim of the study was to evaluate how morphological phenotype impacted upon overall survival. 191 cases of malignant pleural mesothelioma with available follow-up were identified, examined and classified according to histological types. The epithelioid mesotheliomas were further subdivided according to morphological subtypes: myxoid, microcystic, tubulopapillary, solid epithelioid, micropapillary and pleomorphic; biphasic mesotheliomas were divided into epithelioid component dominant and sarcomatoid component dominant; pure sarcomatoid mesotheliomas were divided into not otherwise specified, leiomyoid, desmoplastic and heterologous. All cases were confirmed by two experienced observers. Myxoid variant malignant pleural epithelioid mesothelioma was observed to have a favourable overall survival compared with pleomorphic form (p=0.00008). Pleomorphic phenotype had the worst overall survival. Morphological phenotype is an important histological factor that should be included in pathology reports to convey potential favourable prognostic subgroups of patients with mesothelioma.

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In plain English

This study re-examined archived tumour slides from 191 patients with pleural malignant mesothelioma whose cases were received at University Hospital Llandough between 1987 and 2005 and who had full survival data. The authors classified each tumour by its main type and its microscopic pattern, then compared how long patients survived. The article does not report asbestos or any other exposure. Overall median survival was 13 months. Median survival was 16 months for the 114 epithelioid cases, 12 months for the 37 biphasic cases and 8 months for the 40 sarcomatoid cases. Among epithelioid patterns, the 16 myxoid/microcystic cases had a median survival of 24 months and 50% were alive at 2 years. The 10 pleomorphic cases had a median of 8 months and none survived 2 years. Under the study's significance cutoff (p less than 0.0045), the myxoid/microcystic versus pleomorphic comparison was significant (p=0.000080), as were pleomorphic versus tubulopapillary and versus solid. No significant differences were found within the biphasic or sarcomatoid groups, which the authors said were small. The authors concluded that the pattern of epithelioid mesothelioma should be routinely recorded.

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 archived pathology cases, with survival compared between tumour types and patterns (Kaplan-Meier analysis and log-rank tests)
• Who was studied: 191 patients with pleural malignant mesothelioma with available survival data, from University Hospital Llandough archives, 1987 to 2005; median age 63.7 years (range 29 to 85); male to female ratio 9:1
• Exposure: Not reported. The article gives no information on asbestos fiber types, jobs or doses. The factor compared was the tumour's histological type and pattern.
• Main results:
  • All 191 patients: median overall survival 13 months, 2-year overall survival 16.8%, 5-year overall survival 2.6%
  • By main type: epithelioid (114 patients) had a median survival of 16 months (95% CI 13.2 to 18.8), 2-year survival 24.6% and 5-year survival 5.3%. Biphasic (37 patients) had a median of 12 months (CI printed as 18.3 to 15.7), 2-year survival 2.7% and 5-year survival 0%. Sarcomatoid (40 patients) had a median of 8 months (5.5 to 10.5), 2-year survival 7.5% and 5-year survival 0%.
  • Survival differed significantly between epithelioid and biphasic types (chi-square 10.741, p=0.001) and between epithelioid and sarcomatoid types (chi-square 18.843, p less than 0.001)
  • Epithelioid patterns, median survival (95% CI) and 2-year survival: solid (32 cases) 14 months (9.4 to 18.6), 18.8%; tubulopapillary (48 cases) 17 months (15.1 to 18.9), 29.2%; myxoid/microcystic (16 cases) 24 months (16.2 to 32.8), 50%; pleomorphic (10 cases) 8 months (6.0 to 10.0), 0%; micropapillary (6 cases) 12 months (7.2 to 16.8), 0%
  • Myxoid/microcystic compared with other epithelioid patterns: versus pleomorphic p=0.000080, which was significant under the study's cutoff of p less than 0.0045. Versus tubulopapillary (p=0.084), solid (p=0.040) and micropapillary (p=0.0078), the differences did not reach that cutoff.
  • Pleomorphic compared with other epithelioid patterns: versus tubulopapillary p=0.0032 and versus solid p=0.0011, both significant at the p less than 0.0045 cutoff. Versus micropapillary, p=0.12.
  • Two patients with myxoid variant tumours survived beyond 5 years; the longest survival was 163 months (over 13 years)
  • In the pleomorphic epithelioid group, the longest survival was 17 months
  • Epithelioid-predominant biphasic tumours had better overall survival than sarcomatoid-predominant biphasic tumours, but the difference was not statistically significant
  • Sarcomatoid tumours had poor survival, with no survival difference between their variant forms (leiomyoid, desmoplastic, heterologous, not otherwise specified)
• The authors' conclusion: The authors concluded that the histological pattern of malignant epithelioid pleural mesothelioma should be routinely recorded, because myxoid/microcystic patterns were linked to longer survival and pleomorphic patterns to shorter survival
• Limitations the authors state:
  • Biphasic and sarcomatoid mesotheliomas were few in this cohort, so the authors cautioned against drawing further conclusions about them
  • The authors described their suggested reasons for the better survival with myxoid mesothelioma (such as low proliferation or lower compressive effect) as speculative

Topics

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

Medical terms in this study, explained in our Lexicon: Epithelioid, Pleural Mesothelioma, Prognosis, Malignant Mesothelioma, Overall Survival, Mesothelioma, Tubulopapillary, Micropapillary.

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• Nuclear grade and necrosis predict prognosis in malignant epithelioid pleural mesothelioma: a multi-institutional study — L.E. Rosen, T. Karrison, et al. (2018)
• Is Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy Justified for Biphasic Variants of Peritoneal Mesothelioma? Outcomes from the Peritoneal Surface Oncology Group International Registry — K.I. Votanopoulos, P. Sugarbaker, et al. (2018)
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• A Rare Case of Pleural Epithelioid Mesothelioma With a Prominent Myxoid Stroma Reported With Morphology, Fluorescent In Situ Hybridization, and Ultrastructural Findings — H. Sonobe, R. Omote, et al. (2024)

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