Multidetector CT Findings and Differential Diagnoses of Malignant Pleural Mesothelioma and Metastatic Pleural Diseases in Korea

Our plain-English summary of Multidetector CT Findings and Differential Diagnoses of Malignant Pleural Mesothelioma and Metastatic Pleural Diseases in Korea, by Y.K. Kim, J.S. Kim, K.W. Lee, et al (Korean Journal of Radiology, 2016).

The study

• Authors: Y.K. Kim, J.S. Kim, K.W. Lee, C.A. Yi, J.M. Goo, S.H. Jung
• Journal: Korean Journal of Radiology
• Published: 2016;17(4):545-53
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To compare the multidetector CT (MDCT) features of malignant pleural mesothelioma (MPM) and metastatic pleural disease (MPD).

Materials And Methods: The authors reviewed the MDCT images of 167 patients, 103 patients with MPM and 64 patients with MPD. All 167 cases were pathologically confirmed by sonography-guided needle biopsy of pleura, thoracoscopic pleural biopsy, or open thoracotomy. CT features were evaluated with respect to pleural effusion, pleural thickening, invasion of other organs, lung abnormality, lymphadenopathy, mediastinal shifting, thoracic volume decrease, asbestosis, and the presence of pleural plaque.

Results: Pleural thickening was the most common CT finding in MPM (96.1%) and MPD (93.8%). Circumferential pleural thickening (31.1% vs. 10.9%, odds ratio [OR] 3.670), thickening of fissural pleura (83.5% vs. 67.2%, OR 2.471), thickening of diaphragmatic pleura (90.3% vs. 73.4%, OR 3.364), pleural mass (38.8% vs. 23.4%, OR 2.074), pericardial involvement (56.3% vs. 20.3%, OR 5.056), and pleural plaque (66.0% vs. 21.9%, OR 6.939) were more frequently seen in MPM than in MPD. On the other hand, nodular pleural thickening (59.2% vs. 76.6%, OR 0.445), hilar lymph node metastasis (5.8% vs. 20.3%, OR 0.243), mediastinal lymph node metastasis (10.7% vs. 37.5%, OR 0.199), and hematogenous lung metastasis (9.7% vs. 29.2%, OR 0.261) were less frequent in MPM than in MPD. When we analyzed MPD from extrathoracic malignancy (EMPD) separately and compared them to MPM, circumferential pleural thickening, thickening of interlobar fissure, pericardial involvement and presence of pleural plaque were significant findings indicating MPM than EMPD. MPM had significantly lower occurrence of hematogenous lung metastasis, as compared with EMPD.

Conclusion: Awareness of frequent and infrequent CT findings could aid in distinguishing MPM from MPD.

In plain English

This retrospective study from Korea compared chest CT scans of 103 patients with malignant pleural mesothelioma and 64 patients with metastatic pleural disease, meaning cancer that had spread to the lining of the lung from elsewhere, most often from lung cancer. Every diagnosis was confirmed by tissue examination. Two radiologists who did not know each patient's diagnosis reviewed the scans together. Pleural thickening was the most common finding in both groups: 96.1% of mesothelioma patients and 93.8% of metastatic patients. Pleural plaques were seen in 66.0% of mesothelioma patients and 21.9% of metastatic patients. Pericardial involvement was seen in 56.3% versus 20.3%, and circumferential pleural thickening in 31.1% versus 10.9%. Nodular thickening, enlarged hilar and mediastinal lymph nodes, and spread to the lungs through the blood were less common in mesothelioma. Known asbestos exposure was recorded for 35.0% of mesothelioma patients and 10.9% of the others. The authors concluded that awareness of these findings could aid in distinguishing the two diseases. They noted that the study was retrospective, that different scanners were used, and that the readers knew a malignant pleural disease was present.

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 comparing two groups of patients with pathologically confirmed disease
• Who was studied: 167 patients in Korea: 103 with malignant pleural mesothelioma drawn from the Korean mesothelioma surveillance system database, and 64 with metastatic pleural disease treated at eight tertiary hospitals, 40 of whom had lung cancer. Study dates are not given.
• Exposure: This is not an exposure study. Known asbestos exposure was recorded for 36 of 103 mesothelioma patients (35.0%) and 7 of 64 metastatic disease patients (10.9%), p = 0.001. No fiber types are reported.
• Main results:
  • Pleural thickening was the most common CT finding in both groups: 96.1% of mesothelioma patients and 93.8% of metastatic disease patients.
  • Pleural plaque was seen in 68 of 103 mesothelioma patients (66.0%) and 14 of 64 metastatic disease patients (21.9%); OR 6.939 (95% CI 3.380 to 14.246).
  • Pericardial involvement was seen in 58 mesothelioma patients (56.3%) and 13 metastatic disease patients (20.3%); OR 5.056 (95% CI 2.454 to 10.417).
  • Circumferential pleural thickening was seen in 32 mesothelioma patients (31.1%) and 7 metastatic disease patients (10.9%); OR 3.670 (95% CI 1.509 to 8.928).
  • Some findings were less frequent in mesothelioma than in metastatic disease. Nodular pleural thickening: 59.2% vs 76.6% (OR 0.445). Hilar lymph node enlargement: 5.8% vs 20.3% (OR 0.243). Mediastinal lymph node enlargement: 10.7% vs 37.5% (OR 0.199).
  • Hematogenous lung metastases (spread to the lungs through the blood) were seen in 10 mesothelioma patients (9.7%) and 18 metastatic disease patients (28.1%); OR 0.275 (95% CI 0.117 to 0.643).
  • Compared with the 24 patients whose metastatic disease came from cancers outside the chest, mesothelioma patients more often had circumferential pleural thickening, fissural thickening, pericardial involvement and pleural plaque, and less often had hematogenous lung metastasis. Pleural plaque was seen in 66.0% vs 12.5%, OR 13.600 (95% CI 3.794 to 48.748).
  • Asbestosis was seen on CT in 5 mesothelioma patients (4.9%) and no metastatic disease patients. This difference was not statistically significant (p = 0.158).
• The authors' conclusion: The authors concluded that awareness of frequent and infrequent CT findings could aid in distinguishing malignant pleural mesothelioma from metastatic pleural disease.
• Limitations the authors state:
  • The study was retrospective, and the readers knew a malignant pleural disease was present, which may have increased detection of pleural thickening and enlarged lymph nodes.
  • Different scanners and protocols were used, which could have affected evaluation of thin pleural plaques and mild asbestosis.
  • Lymph node and lung metastases were not confirmed by pathology.
  • The authors suggested that the more frequent lymph node enlargement in metastatic disease may reflect the large share of lung cancer patients in that group.

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: Pleural Mesothelioma, Needle Biopsy, Pleura, Pleural Biopsy, Thoracotomy, Pleural Effusion, Pleural Thickening, Lymphadenopathy.

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