Diagnosis of bronchogenic carcinoma through the cytologic examination of sputum, with special reference to tumor typing.

: The results obtained in the cytologic study of sputa from 630 patients are presented. There were 251 cases of bronchogenic carcinoma; diagnosis through sputum examination was possible in 57.4 per cent of the patients. Abnormal cells were detected in an additional 24.3 per cent. Sputum examination has proven to be a valuable complement by establishing the correct diagnosis when other methods failed. Cancer cells were unequivocally identified in 45.8 per cent of the cases with normal bronchoscopic examination and in 52.4 per cent of the cases in which bronchial biopsy did not include malignant tissue. The same proportion of cases with the various tumor types was obtained by cytologic and by histologic study. However, one of the methods often showed a higher degree of cellular differentiation than the other. The number of cases with undifferentiated cancer or unclassified tumors was markedly reduced when the information concerning cell differentiation available through both methods was used. In this manner, excluding the oat cell carcinomas, only 7.6 per cent of the cases of bronchogenic carcinoma did not show any cellular differentiation. The authors recommend wider use of the information provided by simultaneous evaluation of both cytologic smears and tissue sections in order to achieve a more accurate appraisal of tumor type.