Malignant Pleural Mesothelioma Caused by Environmental Exposure to Asbestos in the Southeast of Turkey: CT Findings in 117 Patients

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.