Malignant pleural mesothelioma caused by environmental exposure to asbestos in the Southeast of Turkey: CT findings in 117 patients

Our plain-English summary of Malignant pleural mesothelioma caused by environmental exposure to asbestos in the Southeast of Turkey: CT findings in 117 patients, by A. Senyiğit, H. Bayram, C. Babayiğit, et al (Respiration; International Review of Thoracic Diseases, 2000).

The study

• Authors: A. Senyiğit, H. Bayram, C. Babayiğit, F. Topçu, H. Nazaroğlu, A. Bilici, I.H. Leblebici
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2000;67(6):615-22
• Cited by: 40 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background And Objectives: Malignant pleural mesothelioma (MPM) is reported to be common in the southeast of Turkey, as a result of environmental asbestos exposure. The aim of this study was to evaluate the computed tomography (CT) features of MPM in patients with a history of asbestos exposure.

Methods: The CT scans of 117 patients who had a diagnosis of MPM were retrospectively evaluated. Additionally, CT findings of histologic subtypes were compared.

Results: The most common CT findings included pleural effusion (n = 104, 89%), pleural thickening (n = 96, 82%), mediastinal pleural involvement (n = 77, 66%) and interlobar fissural involvement (n = 62, 53%). Histologic subtype analysis was performed in 89 patients; of these, epithelial, sarcomatous and mixed types were identified in 46, 23 and 20 patients, respectively. An analysis of CT findings demonstrated that the involvement of mediastinal pleural (91%), interlobar fissure (87%) and lung parenchyma (48%) was significantly more frequent in sarcomatous type, as compared to epithelial (61% and p < 0.01; 35 and 4%, p < 0.0001, respectively) and mixed types (65% and p < 0.05; 10% and p < 0.0001; 10% and p < 0.01, respectively). Furthermore, there was a significant correlation between pericardial involvement and chest wall involvement (r = 0.42, p < 0.05) in sarcomatous type. Similarly, lymphadenopathy and parenchymal involvement (r = 0.23, p < 0.02), pericardial and chest wall involvement (r = 0.25, p < 0.01), chest wall and interlobar fissural involvement (r = 0.25, p < 0.01) were significantly correlated, when CT findings of all histologic subtypes were combined.

Conclusions: These results suggest that although CT findings of MPM vary, they may provide valuable clues to the diagnosis, at least in patients with a history of asbestos exposure. In addition, the presence of extensive lesions may suggest MPM of sarcomatous subtype.

Copyright 2000 S. Karger AG, Basel

In plain English

This was a retrospective review of chest computed tomography (CT) scans from 117 patients (67 men and 50 women, aged 21 to 79) diagnosed with malignant pleural mesothelioma at Dicle University Research Hospital in Diyarbakır, Turkey, between January 1988 and March 1999. All patients had a history of environmental asbestos exposure. Fiber types and doses were not reported for them. The most common CT findings were fluid around the lung (pleural effusion; 104 patients, 89%), pleural thickening (96, 82%), involvement of the mediastinal pleura (77, 66%) and involvement of the fissures between lung lobes (62, 53%). Pleural plaques appeared in 21%. In 3 patients CT showed only fluid, and tumor was found by thoracoscopic biopsy. Among 89 patients with a known tissue subtype, the sarcomatous type (23 patients) more often involved the mediastinal pleura (91%), interlobar fissures (87%) and lung tissue (48%) than the epithelial (46 patients) and mixed (20 patients) types. The authors concluded that CT findings vary but may give valuable clues to diagnosis in asbestos-exposed patients, and that extensive lesions may suggest the sarcomatous subtype.

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 CT scans in patients with diagnosed malignant pleural mesothelioma (case series), with comparison of CT findings between histologic subtypes
• Who was studied: 117 patients (67 men, 50 women; mean age 53.2 years, range 21 to 79) diagnosed with malignant pleural mesothelioma at Dicle University Research Hospital, Diyarbakır, Turkey, January 1988 to March 1999. Diagnosis was pathologically confirmed in all cases. Histologic subtype was analysed in 89 of them.
• Exposure: Environmental (non-occupational) asbestos exposure, as reported in patient history. The article does not report fiber types or doses for these patients. Its introduction describes earlier reports by other authors of local soil containing serpentine and amphibole asbestos and talc that was used as whitewash in homes.
• Main results:
  • Pleural effusion was seen on CT in 104 of 117 patients (89%), pleural thickening in 96 (82%), mediastinal pleural involvement in 77 (66%) and interlobar fissural involvement in 62 (53%).
  • The right side of the chest was affected in 82 patients (70%), the left side in 30 (26%), and both sides in 5 (4%).
  • Pleural plaques were present in 21% of the 117 patients: 18% had hyaline plaques and 3% had calcified plaques.
  • In 3 patients, CT showed pleural effusion but no other pleural abnormality. These patients were diagnosed by thoracoscopic (VATS) biopsy of tiny nodules on the visceral pleura.
  • Of the 89 patients with an identified histologic subtype, 46 were epithelial, 23 sarcomatous and 20 mixed.
  • Mediastinal pleural involvement was more frequent in the sarcomatous type (91%) than in the epithelial type (61%, p less than 0.01) and the mixed type (65%, p less than 0.05).
  • Interlobar fissure involvement was 87% in the sarcomatous type, versus 35% in the epithelial type and 10% in the mixed type (both p less than 0.0001). Lung parenchyma involvement was 48% in the sarcomatous type, versus 4% in the epithelial type (p less than 0.0001) and 10% in the mixed type (p less than 0.01).
  • Compared with the epithelial type, the sarcomatous type had more lymphadenopathy (26% vs 7%, p less than 0.05) and more chest wall invasion (22% vs 2%, p less than 0.01).
  • Pericardial involvement was correlated with chest wall involvement (r = 0.42, p less than 0.05) only in the sarcomatous type. With all subtypes combined, the following were correlated: lymphadenopathy and parenchymal involvement (r = 0.23), pericardial and chest wall involvement (r = 0.25), and chest wall and interlobar fissural involvement (r = 0.25).
  • Chest X-rays detected pleural thickening in 33% of patients, compared with 82% by CT. X-rays showed interlobar fissure and mediastinal pleura involvement in 6% and 21%, compared with 53% and 66% by CT.
• The authors' conclusion: The authors concluded that, although CT findings of malignant pleural mesothelioma vary, they may provide valuable clues to diagnosis, at least in patients with a history of asbestos exposure. They added that the more frequent involvement of the mediastinal pleura, interlobar fissure and lung parenchyma in the sarcomatous type may be evidence of that tumor's invasive character.
• Limitations the authors state:
  • The authors stated that the meaning of the correlations they found between CT findings is not yet known and may be related to the extent of disease.
  • The authors suggested that their lower rate of nodular pleural thickening (21%) compared with another series may reflect patients being in advanced stages of disease.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Environmental Exposure, Asbestos Exposure, CT Scan, Histological Subtype, Pleural Effusion, Pleural Thickening, Parenchyma.

Related studies

• Incidence of malignant pleural mesothelioma due to environmental asbestos fiber exposure in the southeast of Turkey — A. Senyiğit, C. Babayiğit, et al. (2000)
• Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients — A.A. Sahin, L. Cöplü, et al. (1993)
• Environmental asbestos-related pleural plaque in southeast of Turkey — G. Ates, T. Yildiz, et al. (2010)
• Malignant pleural mesotheliomas: an environmental health risk in southeast Turkey — K.M. Müller, M. Fischer (2000)
• High-resolution computed tomography in cases with environmental exposure to asbestos in Turkey — F. Topçu, H. Bayram, et al. (2000)
• Lung diseases due to environmental exposures to erionite and asbestos in Turkey — S. Emri, A. Demir, et al. (2002)

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