Pleural Thickening and Calcification

Pleural thickening and calcification discusses the radiographic and computed tomography (CT) manifestations of benign pleural thickening and pleural calcification. Benign pleural thickening must be differentiated from malignant pleural thickening and their differentiating characteristics will be discussed. Pleural plaque is the most common manifestation of asbestos exposure and carries no risk of malignant degeneration. The most common imaging appearance is bilateral sharply demarcated, multifocal areas of discontinuous pleural thickening that often calcifies over time. Pleural plaques spare the apical and costophrenic sulcus pleura and has a predilection for the diaphragmatic pleura. Diffuse pleural thickening is associated with hemothorax, empyema, connective tissue disorders, and asbestos exposure. It is generally unilateral, causes blunting of the costophrenic angle, spans multiple rib interspaces, and is irregular in shape. When diffuse pleural thickening calcifies and is associated with volume loss in the affected lung, it is termed fibrothorax.

Anthophyllite Asbestos: The Role of Fiber Width in Mesothelioma Induction Part 2: Further Epidemiological Studies of Occupational, Domestic and Environmental Exposure to Finnish Anthophyllite Asbestos

Although people in all sectors of the Finnish anthophyllite industry, including their families, have been heavily exposed to anthophyllite there is no evidence for even a single proven case of attributable mesothelioma. A few cases have been claimed but the evidence either, that they were mesotheliomas or that amphibole exposure was solely to anthophyllite is, in every case examined, insufficient. Even among the population who lived in Karelia in Central Finland who were exposed domestically or enviromentally to anthophyllite released during agricultural and various domestic activities and during transport from the mines, Finnish epidemiology found no risk of mesothelioma. There is also an absence of mesotheliomas reported in the earlier Finnish literature. This anomaly compared to the effects of exposure to other amphiboles is strong support for the role of fiber width in mesothelioma production. Anthophyllite, though, is not without clinical effect. As screening techniques improved it was discovered that of every person over the age of 65 years, one third living in Karelia had bilateral pleural plaques. The area was henceforth called the Endemic Pleural Plaque (EPP) zone. Radiographic analysis of the residents living in the district of Kuusjarvi led to suggestions that the cases resulted from asbestos blown from the Paakila facility via fiber drift as far away as 30 km. Later studies showed that ‘fiber drift’ was very unlikely to be a factor in the radiological findings thus observed.

Occupational and Environmental Lung Diseases Selected Pneumoconiosis

Environmental and occupational lung diseases encompass a diverse group of lung diseases caused by the inhalation of potentially harmful substances. This review provides an in-depth discussion of the pneumoconioses, hypersensitivity pneumonitis, chronic beryllium disease, and other occupational lung diseases that affect the parenchyma. For each disease, the review presents the epidemiology, biologic mechanisms when known, diagnosis, and clinical care. The review includes tables with different pneumoconioses, occupations and industries associated with silicosis and asbestosis, and some selected causes of hypersensitivity pneumonitis, as well as chest radiographs, computed tomographic scans, and/or pathologic slides of some selected diseases. This review contains 9 figures, 4 tables, and 68 references. Key words: asbestosis, asbestos-related pleural plaque, coal worker’s pneumoconiosis, chronic beryllium disease, hard metal pneumoconiosis, hypersensitivity pneumonitis, pneumoconiosis, progressive massive fibrosis, silicosis