Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients

Our plain-English summary of Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients, by A.A. Sahin, L. Cöplü, Z.T. Selçuk, et al (AJR. American Journal of Roentgenology, 1993).

The study

• Authors: A.A. Sahin, L. Cöplü, Z.T. Selçuk, M. Eryilmaz, S. Emri, O. Akhan, Y.I. Bariş
• Journal: AJR. American Journal of Roentgenology
• Published: 1993;161(3):533-7
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: Malignant pleural mesothelioma in rural Turkey frequently results from environmental exposure to tremolite asbestos or fibrous zeolite (erionite). The aim of this study was to determine the CT features of malignant pleural mesothelioma in patients exposed to asbestos or erionite.

Materials And Methods: The CT scans of 84 patients with proved malignant pleural mesothelioma were retrospectively evaluated. Twenty patients (24%) had been exposed to erionite and 64 patients (76%) had been exposed to asbestos. The CT scans were interpreted by seven observers who did not know the clinical or pathologic findings.

Results: CT scans showed either unilateral pleural thickening or pleural nodules/masses in all patients. Pleural nodules were present in 25 patients (30%) and pleural masses in 44 patients (52%). Pleural effusion was found in 61 patients (73%), mediastinal pleural involvement in 78 (93%), pleural calcifications in 52 (62%), involvement of the interlobar fissures in 64 (76%), and volume contraction in 61 (73%). Reduced size of the hemithorax was significantly correlated with chest wall involvement. On the basis of CT findings, the preassigned staging was changed in 21 patients (25%), including 44% of the patients with disease that had been classified as stage I. CT findings were not significantly different between the patients exposed to erionite and those exposed to asbestos.

Conclusion: The most common CT findings in cases of malignant pleural mesothelioma were unilateral pleural thickening or pleural nodules/masses with or without effusion. CT provided valuable information on the extent of the disease, which was important for staging. Although the CT features are not pathognomonic, they provide valuable clues to the diagnosis in patients who have been exposed to mineral fibers.

In plain English

This retrospective study reviewed chest CT scans of 84 patients (51 men, 33 women) with pathologically confirmed malignant pleural mesothelioma seen at Hacettepe University Hospitals in Ankara, Turkey, between 1989 and 1992. None had been exposed to asbestos at work. Twenty came from villages where residents are environmentally exposed to erionite, a fibrous mineral. The other 64 came from villages with environmental asbestos exposure, which the article describes as mainly tremolite asbestos. On CT, pleural soft-tissue lesions were seen in 69 patients (25 with nodules, 44 with masses). Other findings were pleural effusion in 61 (73%), mediastinal pleural involvement in 78 (93%), involvement of the interlobar fissures in 64 (76%), reduced volume of the affected side of the chest in 61 (73%), and calcified pleural plaques in 52 (62%). CT findings moved 17 of the patients first classified as stage I (44%) to a higher stage. CT findings did not differ significantly between the erionite and asbestos groups. The authors concluded that no CT finding is specific to mesothelioma, but that CT gives valuable clues to the diagnosis in people exposed to mineral fibers.

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 (case series). Seven readers who did not know the clinical or pathologic findings read the scans.
• Who was studied: 84 patients (51 men, 33 women) with pathologically confirmed malignant pleural mesothelioma, seen at Hacettepe University Hospitals, Ankara, Turkey, 1989 to 1992. Twenty (24%) came from three erionite-exposed villages in central Turkey and 64 (76%) from asbestos-exposed villages. Ages ranged from 26 to 76 years.
• Exposure: Non-occupational, environmental exposure to tremolite asbestos (mainly) or to erionite, a fibrous zeolite. Exposure group was assigned by the village of origin. No patient had occupational asbestos exposure.
• Main results:
  • Pleural nodules or masses were seen in 69 of 84 patients (82%): 25 had nodules and 44 had masses.
  • Pleural effusion was seen in 61 patients (73%). It was massive in 24 and moderate in 37.
  • The mediastinal pleura was involved in 78 patients (93%).
  • The interlobar fissures were involved in 64 patients (76%).
  • The affected side of the chest was contracted in 61 patients (73%), all of whom showed rib crowding. Volume reduction was seen in every patient with chest wall involvement except one (reported as statistically significant).
  • Calcified pleural plaques were seen in 52 patients (62%) and were on both sides in 19 of them. By group, they were seen in 11 of the 20 erionite-exposed patients and 41 of the 64 asbestos-exposed patients, a difference that was not statistically significant.
  • Hyaline pleural plaques on the opposite (unaffected) side were seen in 22 patients (26%).
  • CT findings changed the stage in 17 patients previously classified as stage I, which was 44% of the stage I patients.
  • CT findings were not significantly different between the erionite-exposed and asbestos-exposed patients.
• The authors' conclusion: The authors concluded that CT findings in malignant pleural mesothelioma vary and that none is specific (pathognomonic) for the disease. However, in patients exposed to mineral fibers, CT findings provide valuable clues to the diagnosis.
• Limitations the authors state:
  • Lung tissue (parenchymal) disease was not assessed, because patients were not scanned lying face down and high-resolution CT was not used.
  • Lung nodules regarded as metastases in eight patients were not confirmed by tissue examination.
  • Pericardial invasion and mediastinal lymph node enlargement were difficult to assess, because the tumor involved the adjacent mediastinal pleura.
  • CT missed chest wall invasion that was found at surgery in 3 of 18 operated patients.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Environmental Exposure, erionite, Tremolite, Zeolite, CT Scan, Pleural Thickening, Pleural Effusion.

Related studies

• Malignant pleural mesothelioma due to environmental mineral fiber exposure in Turkey. Analysis of 135 cases — Z.T. Selçuk, L. Cöplü, et al. (1992)
• Malignant pleural mesothelioma caused by environmental exposure to asbestos in the Southeast of Turkey: CT findings in 117 patients — A. Senyiğit, H. Bayram, et al. (2000)
• CT findings in malignant pleural mesothelioma related to nonoccupational exposure to asbestos and fibrous zeolite (erionite) — C. Erzen, M. Eryilmaz, et al. (1991)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Lung diseases due to environmental exposures to erionite and asbestos in Turkey — S. Emri, A. Demir, et al. (2002)
• Cohort study of mortality of vermiculite miners exposed to tremolite — J.C. McDonald, A.D. McDonald, et al. (1986)

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