What Is a Lung Nodule?


Quick Answer

A lung nodule is a small mass of tissues in the lung. It appears as round, white shadows on a computerized tomography scan or a chest X-ray. Typically, lung nodules are approximately 0.2 inch to 1.2 inches in size. A bigger lung nodule of up to 30 millimeters is more likely to be cancerous than a smaller lung nodule.

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What Is a Lung Nodule?
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Full Answer

Lung nodules are categorized as benign lung nodules, nodules from inflammation, and fibrosis and malignant lung nodules. A benign nodule usually does not spread to other areas. However, their presence, especially if they are big, may cause health problems. Two types of benign nodules include granulomas and hamartomas. Lung nodules caused by infections are classified as bacterial infections (for instance, tuberculosis, fungal infections such as histoplasmosis, coccidioidomycosis and parasitic infections including pneumocystis carinii pneumonia in an immune deficient patient).

Conditions that lead to inflammation and fibrosis can make one susceptible to benign lung nodules. These conditions include rheumatoid arthritis, Wegener’s granulomatosis, rounded atelectasis, sarcoidosis, bronchogenic cysts, focal hemorrhage, healed pulmonary infarcts, multiple recurrent bronchpneumonias and hemangiomas. Malignant lung nodules include lung cancers, lymphomas and cancers that spread to the lungs from other body parts. Causes of these types of lung nodules include genetic predisposition, smoking history and exposure to toxic materials.

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