Topics in Lung Disease: Pulmonary Nodules.

Pulmonary nodules are commonly detected during routine lung cancer screening on low-dose chest computed tomography (CT) or incidentally on other imaging. Approximately 1.6 million people in the United States are diagnosed with pulmonary nodules annually, with most being asymptomatic. The etiology of pulmonary nodules ranges from benign to malignant, necessitating a structured approach to evaluation. The US Preventive Services Task Force recommends lung cancer screening for high-risk individuals because it reduces lung cancer mortality. Management of pulmonary nodules relies on statistical models to estimate malignancy risk by incorporating radio-graphic features and clinical history. The Fleischner Society provides guidelines for managing incidentally detected nodules, whereas the Lung CT Screening Reporting and Data System offers a framework for risk stratification and surveillance. Radiographic characteristics suggestive of malignancy include part-solid or ground-glass appearance, large nodule size, spiculated margins, vascular convergence, and pleural retraction. Risk factors such as smoking history, older age, chronic obstructive pulmonary disease, cancer history, and environmental or occupational expo-sure to toxins further increase the probability of malignancy. Management strategies are dependent on malignancy risk and may include serial imaging for low-risk nodules and invasive procedures such as biopsy or surgical resection for high-risk lesions. Referral to a specialist is warranted for nodules with a high likelihood of malignancy or if tissue diagnosis is required.