Diagnostic Value of Computed Tomography Imaging Features in Malignant Pleural Mesothelioma.

Background: Medical history, thoracentesis, and imaging features are usually the first steps in the investigation of a possible malignant pleural effusion (MPE). Unfortunately, the diagnostic yield of thoracentesis in this situation is suboptimal even if the procedure is repeated, especially in the context of malignant pleural mesothelioma (MPM). The next step for confirming the diagnosis, if clinically appropriate, is thoracoscopy, but not all patients are fit to undergo this procedure, so the diagnosis is then based on the medical history and imaging features only.

Objectives: Our objective was to evaluate the diagnostic value of the medical history and imaging features in MPM.

Methods: We reviewed the imaging and medical charts of 92 patients with a final diagnosis of MPE included in our prospective medical thoracoscopy database. The clinical characteristics and imaging features of patients with primary MPE were compared with those of patients with secondary MPE.

Results: Male sex (82 vs. 59%, p = 0.02), asbestos exposure (58 vs. 10%, p < 0.001), and mediastinal (68 vs. 33%, p = 0.04), diaphragmatic (75 vs. 31%, p = 0.001) and circumferential pleural thickening (55 vs. 19% p = 0.001) were significantly more frequent in MPM patients. In a multivariate linear regression model, only asbestos exposure (OR 11.2; 95% CI 3.4-36.9) and circumferential pleural thickening (OR 4.7; 95% CI 1.6-13.9) were significantly associated with a diagnosis of MPM.

Conclusion: In situations where it is impossible to obtain adequate pleural samples to differentiate MPM from a secondary pleural malignancy, the combination of circumferential pleural thickening and a history of asbestos exposure may be sufficient to make a clinical diagnosis.