Computed tomography of localized pleural mesothelioma

Our plain-English summary of Computed tomography of localized pleural mesothelioma, by C.G. Dedrick, T.C. McLoud, J.A. Shepard, et al (AJR. American Journal of Roentgenology, 1985).

The study

• Authors: C.G. Dedrick, T.C. McLoud, J.A. Shepard, R.T. Shipley
• Journal: AJR. American Journal of Roentgenology
• Published: 1985;144(2):275-80
• Cited by: 67 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The computed tomographic (CT) features of six pathologically proven cases of fibrous mesothelioma were reviewed. There were no pathognomonic CT characteristics, but in all cases CT suggested or supported the preoperative diagnosis. CT findings included well delineated, often lobulated, noncalcified soft-tissue masses in close relation to a pleural surface, associated crural thickening, and absence of chest wall invasion. An obtuse angle of the mass with respect to the pleural surface was not particularly useful. Rather, a smoothly tapering margin was more characteristic of a pleural lesion.

In plain English

This article reviewed, retrospectively, the chest CT scans of six patients with localized fibrous pleural mesothelioma. The authors called this tumor benign, as distinct from the diffuse malignant form. The scans were done before surgery during 1982 and 1983, and the authors worked in radiology at Massachusetts General Hospital in Boston. The patients were five men and one woman aged 51 to 68. Two had a history of asbestos exposure during World War II; no fiber type was named. On CT, all masses were smooth, sharply delineated and noncalcified, and five of six had uniform soft-tissue density. None formed the obtuse angle with the chest wall often cited as a sign of pleural lesions. Instead, all five masses at the edge of the chest had smoothly tapering margins. CT showed pleural plaques in one patient. Biopsies attempted in four patients before surgery were nondiagnostic, and the diagnosis was made at surgery. The authors reported that CT advanced or strongly supported the diagnosis in all six cases. They concluded that no radiologic feature is pathognomonic, meaning unique to this tumor.

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 case series reviewing CT and other imaging features
• Who was studied: Six patients (five men and one woman, aged 51 to 68) with a surgical diagnosis of fibrous (benign) mesothelioma who had chest CT before surgery during an 18-month period in 1982 and 1983; the authors were from the Department of Radiology, Massachusetts General Hospital, Boston
• Exposure: The study did not examine asbestos exposure as such. Two of the six patients had a history of asbestos exposure during World War II; no fiber type, job or dose was given. The exposure studied was diagnostic imaging (CT).
• Main results:
  • CT advanced or strongly supported the diagnosis of localized pleural mesothelioma in all six cases
  • All six masses were smoothly contoured, sharply delineated and noncalcified on CT; five of six were of homogeneous soft-tissue density, and the one inhomogeneous mass had areas of necrosis at pathology
  • In none of the six cases did CT show an obtuse angle with the chest wall or fissure
  • Smooth, sharply delineated, tapering margins where the mass met the normal pleura were found in all five peripheral mesotheliomas
  • Diaphragmatic crural thickening was seen in one of the five peripheral cases
  • On CT, pleural effusions were seen in two patients and pleural plaques in one; on plain chest radiographs, pleural findings suggestive of asbestos exposure and asbestosis were consistently absent
  • In five of the six cases, CT distinguished the tumor from adjacent structures such as the descending thoracic aorta, thoracic spine and chest wall; in the sixth, sonography localized the hemidiaphragm
  • No case had a histopathologic diagnosis before surgery. Needle aspiration biopsies (three patients) and a thoracentesis with pleural biopsy (one patient) were all nondiagnostic.
  • In five of the six cases, the radiologist suggested the correct diagnosis based on both standard radiographic and CT features
• The authors' conclusion: The authors concluded that CT can increase preoperative diagnostic accuracy but that no radiologic feature is pathognomonic for localized fibrous pleural mesothelioma. They found a gradually tapering interface between mass and chest wall to be a more reliable sign of pleural origin than the obtuse-angle rule.
• Limitations the authors state:
  • Patient position was not changed during the CT examinations. The authors noted a published report that pedunculated tumors can change location and shape between supine and prone positions.
  • The authors could not explain why none of the tumors formed obtuse angles

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, Mesothelioma.

Related studies

• Surface of localized pleural plaques quantitated by computed tomography scanning: no relation with cumulative asbestos exposure and no effect on lung function — J. Van Cleemput, H. De Raeve, et al. (2001)
• Massive localized malignant pleural mesothelioma (LMPM): manifestations on computed tomography in 6 cases — W. Yao, H. Yang, et al. (2015)
• Preoperative computed tomography does not predict resectability in peritoneal carcinomatosis — J.D. Rivard, W.J. Temple, et al. (2014)
• Performing high-resolution computed tomography in asbestos-exposed patients — T.C. McLoud (1995)
• Predictive accuracy of the Liverpool Lung Project risk model for stratifying patients for computed tomography screening for lung cancer: a case-control and cohort validation study — O.Y. Raji, S.W. Duffy, et al. (2012)
• High resolution computed tomography and lung function in asbestos-exposed workers with normal chest radiographs — C.A. Staples, G. Gamsu, et al. (1989)

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