Small cell lung carcinoma with marked bronchial epithelial involvement

Marked involvement of bronchial epithelium by malignant cells with a neuroendocrine immunophenotype was observed in a pulmonary lobectomy specimen containing combined small cell lung carcinoma (SCLC). Review of the medical literature reveals scant information on malignant neuroendocrine cells in bronchial epithelium accompanying SCLC and no documentation of an SCLC precursor. We discuss the possibility that the intraepithelial neoplastic lesion that we have described may be a primary lesion and possibly a precursor of SCLC and the alternative possibility that it represents invasion by underlying invasive SCLC. The need for further comprehensive study of the morphology and immunophenotype of bronchial mucosal abnormalities accompanying SCLC utilizing lung resection specimens is emphasized.