A lung nodule is a small growth in the lung. Lung nodules are smaller than three centimeters in diameter. A growth larger than three centimeters is called a lung mass.

Most lung nodules are benign (benign). Benign lung nodules can have a wide variety of causes, including:

• Infections
• Noninfectious disorders such as sarcoidosis, granulomatosis with polyangiitis (GPA), and rheumatoid arthritis
• Neoplasms

In some cases, a nodule may be cancerous. Causes of malignant lung nodules include:

• Lung cancer
• Lymphoma
• Carcinoid
• Sarcoma
• Metastatic tumors

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Signs & Symptoms

There are usually no symptoms associated with lung nodules. Most of the time, a patient is unaware that he or she has a lung nodule until a chest X-ray or CT scan of the lungs is done.

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Diagnosis

Lung nodules are normally detected during a chest x-ray or CT scan.