Cytogenetic study of malignant and benign effusions.

The direct chromosome study of mitotic cells in effusions was performed in 49 patients with malignant and 5 with benign effusions. Cytogenetic analysis correctly identified 69.3% of malignant effusions, standard cytology 79.6%. With both methods combined 95.9% of all cases were correctly diagnosed as malignant. The presence of mitoses in the effusions was found to be an unfavorable prognostic sign and was correlated with a shorter survival. Chromosome analysis of the malignant effusions revealed stemlines with extensive numerical and structural rearrangements. No consistent marker chromosome was detected in the histologically similar tumor types. Normal chromosomes. No 1 and 14 were preferentially lost from the karyotype of malignant cells. In two samples double minutes were observed.