Mesothelioma Compared to the Other Pleural Diseases
(Last Update : 21 November 2020)
Mesothelioma is a malignancy pleural mass characterized by pleural thickening, that difficult to distinguish from other pleural disorders, such as infection, asbestosis, pleural effusion/empyema. This case report is interesting and important because chest x-ray and chest CT have characteristics of pleural abnormalities that can be used as guidelines for the diagnosis of Mesothelioma. A 56 years old woman with cough, chest pain and breathlessness since a few days ago, and it was getting worse.
In the chest auscultation, vesicular voices weaken in both lungs. In chest x ray finding a thin opacity on both hemithorax. The left sinus costophrenicus was blunt. Chest CT finding a pleural thickening in the posterobasal of the chest wall and disseminating to the mediastinum – paraaortic and found an osteodestruction of rib bones. Pleural thickening is circumferensial, lobulated, irregular nodular opasities and calsification. The histopathology is malignant epitheloid cell forms a cohesive nest, glandular structure and a lot of micropapillae in accordance with malignant mesothelioma.
Malignant pleural thickening has lesion characteristic of “irregular nodular opacities” on the periphery with or without pleural effuse in chest x ray and in chest CT shows the form of lesions are circumferential, lobulated, encase lung parenchyma.
How are the characteristic of the description of radiology in the chest x ray and CT scan in the mesothelioma compared to other pleural disorders (tuberculosis and fungal infections)? Several pleura disorders in the chest x ray have some benign or malignant characteristics and are caused by infection or not. The pleura lesion characteristics in the chest x ray are based on their causes. Those are malignant mesothelioma signed by the irregular nodular picture which is seen in the chest wall periphery part with or without pleural effusion.
Pleural effusion in the mesothelioma is usually unilateral, the thickening of pleura is massive and getting wider through the fissure interlobar Mesothelioma encases the lung surface (lung encasement) causing the lung‘s volume decreases “loss of lung volume”, diaphragm elevation, mediastinum and retraction of hemithorax and spatial intercostal in the lesion area. Pleural thickening is in the form of nodular (nodular pleural thickening), circumferential and pleural wall thickening is more than 1 cm.
Pericardial, pleural thickening looked irregular is called by a “shaggy” cardiac silhouette, and the surface of the diaphragm which is looked irregular and non-slippery edges is called by “ill-defined diaphragmatic contours”. Pleural thickening in mesothelioma is sometimes accompanied by plaque /classification which looks lined up. The location of the pleural thickening in mesothelioma usually is in the part of lung basal or medio basal hemithorax.
Chest CT scan in the mesothelioma shows more clearly than chest x ray. Pleural thickening as well as pleural effusion and pleural classification as well as lymphonodi around hillus or mediastinum look more clearly and can be differentiated. The spread of lesion in the mesothelioma both intrathoracic and extrathoracic, and bone and soft tissue involvement around the lesion can be better assessed. Chest CT scan can assess the mesothelioma in more detail, pleura thickening circumferential (sensitivity 41%, specificity 100%), parietal pleural thickening > 1 cm (sensitivity 36%, specificity 94%), nodularity (sensitivity 51%, specificity 94%) and the involvement of mediastinum pleural (sensitivity 56%, specificity 88%).
Diffuse pleural thickening which is benign is caused by asbestosis, the side effect of radiotherapy and infections (the most frequent is tuberculosis and empyema). Asbestos is a particle which is very small (it’s different from the dust particle in general). It can go through lung filtration system and enter the lungs, embedded in the pleura and another area such as interstitium. Thus, it causes inflammation and the formation of pleural plaque or “scarring”. Pleural thickening in tuberculosis usually occur in the lungs apex and accompanied by fibrosis tissue in the pulmonary parenchyma. The classification is usually in the thickening pleura, and it can happen in the pulmonary parenchyma in the form of calcification nodules
Pleural thickening leading to a malignant and benign lesion on chest x ray and CT scan has a different characteristic. Malignant mesothelioma (malignant pleural thickening) has lesion characteristic of “irregular nodular opacities” that can be seen on the periphery with or without pleural effuse. The characteristic of mesothelioma on the chest CT scan shows the lesion in the form of circumferential, lobulated, encase lung parenchyma. The soft tissue mass often occurs on the interlobar fissure of pleural classification, especially on the thoracic wall of the basal aspect.
Pleural thickening which leads to benign has the characteristic that depends on its causes. Pleural thickening caused by the infiltration of asbestos in the lungs and pleura has a description as a scar on the hemithorax wall with its specific location can be anywhere on this wall. Asbestosis is the classification of bilateral pleura and diffuse pleural thickening. Pleural thickening caused by the infection of tuberculosis has a characteristic of fibrosis tissue with classification and location usually are in the lungs apex. This benign pleural thickening usually involves the lesion in the pulmonary parenchyma accompanied by consolidation with fibroinfiltrate and calcification.
Reference Sources:
- Majdawati, A. (2018). The Radiology Characteristic of Pleural Thickening Lesion: Mesothelioma Compared to the Other Pleural Diseases. Mutiara Medika: Jurnal Kedokteran dan Kesehatan, 18(2), 71-76. (LINK)active link as of November 21, 2020
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