Radiology Key

Etiology Lung cancer arises when cells lining the bronchi or peripheral airways undergo neoplastic change in response to an inciting agent or agents. The most common and well-recognized cause of…

Schemes for Staging The most widely used scheme for staging non–small cell lung cancer (NSCLC) is the TNM classification. A variety of alterations in this scheme have been made to…

Overview Etiology, Prevalence, and Epidemiology Tuberculosis (TB) is a chronic recurrent contagious infection caused by Mycobacterium tuberculosis. M. tuberculosis is an aerobic, nonmotile, non–spore-forming rod that is highly resistant to…

Viruses are the most common cause of respiratory infection and may result in rhinitis, pharyngitis, laryngotracheitis, bronchitis, bronchiolitis, and, less commonly, pneumonia. Most viral pneumonias in immunocompetent adults are due…

Etiology, Prevalence, and Epidemiology Inflammatory pseudotumor, also known as inflammatory myofibroblastic tumor, is a quasineoplastic lesion that clinically and radiologically tends to mimic a malignant neoplasm and that histologically consists…

Neuroendocrine Hyperplasia and Pulmonary Tumorlets Etiology, Prevalence, and Epidemiology Normal lung tissue contains scattered neuroendocrine (Kulchitsky) cells within the bronchial and bronchiolar epithelium. These cells play a role in the…

Etiology, Prevalence, and Epidemiology Pulmonary hamartomas are benign neoplasms, probably derived from bronchial wall mesenchymal cells. Hamartomas are the most common benign pulmonary neoplasm and account for about 8% of…

Parasites are defined as organisms that live in or on another living organism, obtain part or all of their organic nutriment from that organism, and cause some degree of damage…

A variety of nontuberculous mycobacteria (NTMB) can cause pulmonary infections, with important differences in epidemiology, microbiology, host response, and treatment options across the various species. The severity of an infection…

Background Lung cancer is the third most common cancer and the leading cause of cancer-related death in the United States. The most important risk factor for lung cancer is smoking,…