Precursor lesions of lung tumors

Abstract

Lung cancer is the leading cause of cancer deaths globally with many new cases diagnosed each year. Recent studies have shown that an accumulation of various genetic abnormalities results in progressive morphologic changes in bronchial epithelium. Such changes are part of the continuum from precursor lesions to invasive lung cancers. Improvement in diagnostic modalities has made the detection of such preneoplastic lesions possible and resection at this stage confer excellent prognosis. The World Health Organization (WHO) has recognized atypical adenomatous hyperplasia/ adenocarcinoma in situ, squamous dysplasia/ squamous cell carcinoma in situ, and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia as the precursor lesions of adenocarcinoma, squamous cell carcinoma, and carcinoid tumors respectively. This review summarizes the key features of these preneoplastic lesions based on the current understanding and knowledge.