Abstract
We examined 3 patients with squamous cell carcinoma of the hilar type among chromate workers for assessment of its development. Diagnosis of the cases was confirmed. by fiberoptic bronchoscopy. We reviewed changes in the bronchial mucosa by fiberoptic bronchoscopy and also successive changes of sputum cytology. The duration between the first bronchoscopic examination which revealed almost normal findings and the second one which revealed carcinoma was 15, 30 and 43 months. By histopathological examination, their stages were defined as carcinoma in situ, micro-invasion and advanced type. These findings strongly suggest that bronchoscopic examination at inter-vals of 15 months or less is the best method to detect in situ squamous cell carcinoma of hilar type.
