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 at computed tomography (CT). This report describes the CT findings in five cases of pleural mesothelioma. In each case the CT showed an extensive, irregular, pleuralbased 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. Malignant pleural mesothelioma is a rare, often difficult to diagnose tumor arising from the surface lining cells or mesothelium. The chest film findings are well described in the literature [1, 2], but there are only isolated descriptions of the findings on computed tomography (CT) [3, 4]. We have seen five cases of pleural mesothelioma in the past year, all studied with CT. Case Reports Case 1 A 59-year-old nun with no known exposure to asbestos had shortness of breath and chest pain. The chest film showed opacification of most of the right chest and pleural thickening. There was no free fluid on the decubitus film, and there was no disease identified in the left thorax. Open chest biopsy showed extensive tumor surrounding the right lung; the pathologic diagnosis was fibrosarcomatous mesothelioma. Chest CT showed a large mass of varying attenuation in the right base involving the lateral chest wall and the mediastinum, displacing the mediastinum anteriorly to the left, and crossing into the left chest (fig. 1 A). The mass extended superiorly to surround the entire right lung (fig. 1 B). The patient was treated with radiation and chemotherapy, and is alive 6 months after diagnosis. Case 2 Received January 5, 1981: accepted after re- vision April 10, 1981. ‘All authors: Department of Radiology, University of Cincinnati Medical Center, Cincinnati Gen- eral Division, 234 Goodman St., Cincinnati, OH 45267. Address reprint requests to E. Alexander. AJR 137:287-291, August 1981 0361 -8o3x/81 / 1372-0287 $00.00 © American Roentgen Ray Society A 68-year-old retired television repairman with no known asbestos exposure had dyspnea and cough for several weeks. The chest film showed a large loculated right pleural effusion. With conservative treatment the effusion persisted. Cope needle biopsy showed anaplastic malignant cells, site unknown. The rest of the diagnostic workup was negative. The patient was treated with chest tube drainage and intrapleural bleomycin. He did reasonably well for about 6 months; then he had nonpleuritic right chest pain and weight loss. The chest film was unchanged. Chest CT showed an irregular pleural mass of variable attenuation encircling the right lung and extending into the major fissure posteriorly.