Oat cell carcinoma of the bronchus and the carcinoid syndrome.

A man with high urinary levels of 5-hydroxyindole acetic acid had an oat cell carcinoma of the bronchus. The patient had symptoms of the carcinoid syndrome and at autopsy was found to have evidence of carcinoid heart disease. This report supports the hypothesis that bronchial carcinoids and oat cell carcinomas are derived from argentaffin (Kulchitsky)-type cells of the lung.