Biochemical and cytological features of diffuse mesotheliomas of the pleura.

The malignant mesothelioma was proved by autopsy as cause for death in 55 cases--42 men and 13 women. 4 men had the tumor without pleural effusion. Transthoracic fine needle biopsy confirmed the suspicion 3 times. The fluids caused by the tumor were exudates 50 times. One fluid was a transudate. Cytological examinations led to the partition into four sections with the following main findings: histiocytes, mesothelial cells also in clusters, tumor cells--21 cases; tumor cells without perceptibility of the matrix--18 cases; cytological empty sediments--8 cases; finding of inflammation--4 cases. The determination of the level of hyaluronic acid in pleural fluids by a colorimetric test proved a malignant mesothelioma in one third of these cases. The synopsis of the named parameters together with clinical dates in general use gives the possibility to put up the diagnosis of the primarily malignant disease of the pleura during lifetime of a patient.