Pleural mesotheliomas--an analysis of 18 cases and review of the literature.

Eighteen cases of mesothelioma, 7 benign and 11 malignant, were analyzed retrospectively. There were 5 females with benign tumors and 10 males with the malignant variety. The mean age was 59 years in the benign group and 55 years in those with malignant tumors. Exposure to asbestos was documented in one benign and five malignant mesotheliomas. Three patients with benign lesions were asymptomatic on presentation while all 11 with malignant tumors had symptoms, chest pain and dyspnea being the most frequent. Abnormal physical findings were rarely noted in the benign group while all the malignant tumors had abnormal findings on presentation. Signs of a pleural effusion were the most common abnormal physical findings, occurring in 8 of 11 patients. Pleural effusion was the most common roentgenologic finding in malignant mesotheliomas, while a mass lesion was the presenting finding in six of seven of the benign group. Pleural effusion was a usual accompaniment of malignant tumors and was an exudate, usually hemorrhagic with leukocyte counts up to 20,000/mm3. Thoracotomy established the diagnosis in each of the five benign and seven malignant cases in which it was attempted. Pleural biopsy was diagnostic in three of six with malignant and one of two with benign tumors. Pleural fluid cytology did not yield a diagnosis in the seven instances in which it was studied. Excisional surgery was performed in five of the benign cases and all have survived one to six years. No treatment was curative of malignant mesotheliomas. Ten of the 11 with malignant tumors died from 3 to 24 months after onset of symptoms (mean 9.9 months). The clinical features of 82 benign and 160 malignant mesotheliomas from selected series in the literature are reviewed and compared with the present series. The roentgenographic features of 51 benign and 87 malignant tumors are also presented. The clinical and diagnostic features which help differentiate mesotheliomas from bronchogenic carcinomas are discussed. A careful approach to the diagnosis of malignant mesotheliomas may help avoid an unnecessary thoracotomy.