Radiology Key

Etiology Leukemias are a group of malignancies in which abnormal cells, usually abnormal white blood cells (leukocytes), are produced in the bone marrow. Leukemias may be classified as myeloid, also…

Etiology Fungal infections of the chest can be divided into two groups based on pathogenesis. The first group is composed of endemic fungi, including Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis,…

Etiology Since the recognition of human immunodeficiency virus (HIV) infection as the cause of acquired immune deficiency syndrome (AIDS) in the 1980s, many changes have occurred in the demographics, complications,…

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…