[Application of electron microscopy in the diagnosis of fine needle aspiration biopsies and tumorous pleural effusion].

Forty-five cases of fine needle aspiration biopsies of tumor and 9 cases of tumorous pleural effusion specimens were reviewed electron microscopically for diagnosis. Among them, electron microscopical diagnosis of 22 cases (40.7%) was valuable, and that of 28 cases (51.8%) was of no diagnostic significance. In 14 out of 22 cases (63.6%) the nature and origin of tumor were further confirmed by electron microscopy, and in 8 cases (36.4%) electron microscopical diagnoses were consistent with light microscopic diagnoses. It was shown that in cytological diagnosis of tumors, electron microscopy was superior to light microscopy in defining the nature and origin of tumors, and in differentiating neuroendocrine tumors, leukemia and small round cell tumors.