Diagnostic and therapeutic challenges following the cytologic diagnosis of in situ carcinoma of the lung.

Clinical challenges associated with the cytologic detection of eight cases of occult pulmonary carcinoma are presented. The pulmonary lesions were successfully localized and resected in three of six cases encountered since the availability of flexible fiberoptic bronchoscopy and selective bronchial brushing. Two of the resected neoplasms were unequivocally in situ, while preoperative radiotherapy precluded accurate pathologic determination of invasiveness in the third. The reported experience with unequivocal in situ bronchogenic carcinoma localized and treated surgically prior to invasion through the basement membrane now totals 17 cases (15 previously reported). Forty-four additional cases (43 previously reported) have been localized and resected following early invasion. From this group totaling 61 occult carcinomas, only two patients (3 percent) are known to have died of pulmonary carcinoma during a followup ranging from 2 to 20 years.