Small cell lung carcinoma Small cell lung cancer Oat cell lung cancer Oat cell carcinoma of lung Small cell lung cancer (SCLC) is a type of highly malignant lung cancer that is composed of small ovoid cells. In the past, SCLC was called oat cell carcinoma because the microscopic appearance of the cells was felt to resemble oats. SLCLC usually originates near the bronchi and in many cases may grow and metastasize quickly. SNOMEDCT_US:254632001 UMLS:C0149925 SNOMEDCT_US:254633006 Neoplasm of the lung