[Pleural effusion cytology of asbestos-associated malignant mesothelioma and lung carcinoma in the diagnosis of occupational diseases by the statutory accident insurance funds].

Pleural effusion often represents the first clinical symptom of lung carcinoma and malignant mesothelioma. As pleural punctation is performed quite early in the diagnostic procedure, effusion cytology frequently gives the first evidence about the presence of tumour cells and tumor histogenesis. In this study, we report on seven cases which were evaluated in our institution for the Employers' Liability Insurance Association, based solely on cytology findings.The mean age of the seven patients with a given long-term asbestos exposure during their working life was 81.7 years. On average eight smears per patient were investigated. In addition to routine cytology, immunocytochemistry, DNA image cytometry, AgNOR-analysis and fluorescence in situ hybridization were applied in a case-specific way. The results were interpreted against the clinical and occupational history of the respective patient.Definitive diagnosis could be made in six cases. In three of them, the diagnosis of malignant mesothelioma was made. Two cases were diagnosed as malignant effusion due to metastatic lung cancer. In one case, cells of high-grade Non-Hodgkin's lymphoma (NHL) were diagnosed and a malignant mesothelioma was excluded. In the last case, malignant mesothelioma could not be diagnosed unequivocally by cytology. In all seven cases, our interpretation was accepted by Employers' Liability Insurance Association. The five mesothelioma or lung cancer cases were accepted as asbestos-associated occupational disease, while the NHL case was rejected. In the last case, malignant mesothelioma was diagnosed later by autopsy, and the case was retroactively accepted as occupational disease.Cytology-based tumor diagnosis including adjuvant methods is a useful and reliable approach in cases of asbestos-associated tumours. Acceptance of occupational disease on the basis of cytological diagnoses even by the Employers' Liability Insurance Association helps avoid invasive pleural or lung biopsies in cases with an unequivocally positive effusion cytology of lung cancer or malignant mesothelioma.