CT of malignant pleural mesothelioma.

Malignant pleural mesothelioma is a rare tumor. Although the chest film findings of pleural mesothelioma are well described, there are few descriptions of the findings of computed tomography (CT). This report describes the CT findings in five cases of pleural mesothelioma. In each case the CT showed an extensive, irregular, pleural-based mass surrounding the lung, spreading into the fissures, and extending into the mediastinum. In two cases there was also extension into the contralateral chest, and in one case each there was extension into the abdomen and chest wall. In each case the chest radiographs underestimated the extent of disease, when compared to CT. When an irregular, pleural-based mass involving most of the hemithorax is identified on CT, the diagnosis of mesothelioma can be suggested and at the same time the extent of the tumor may be evaluated. This is important because the diagnosis of mesothelioma is difficult and because treatment and prognosis may depend on the extent of the disease.