Application of electron microscopy in the definitive diagnosis of effusions.

Electron microscopy was performed on a series of body cavity fluid specimens to evaluate the usefulness of this technique in the diagnosis of effusions. During a six-month period, 42 specimens were examined, 19 benign and 23 malignant. In two cases, the electron microscopic findings were crucial to the diagnosis. In a third case, electron microscopy helped to confirm the diagnosis and avoid unnecessary surgery. In a number of other cases, ultrastructural evaluation demonstrated special cell characteristics not evident in routine light microscopic studies. Based on these findings, we conclude that electron microscopy has a definite place in the diagnosis of effusions and should be increasingly utilized on a selective basis in the evaluation of body cavity fluid specimens. In addition, electron microscopic studies on cells in effusions provide an excellent source of material for educational and research purposes.