Definition of Solitary pulmonary nodule:

A solitary pulmonary nodule is a round or oval spot (lesion) in the lungs that is seen with a chest x-ray or CT scan.

Causes, incidence, and risk factors:

More than half of all solitary pulmonary are noncancerous (benign). Benign nodules have many causes, including old scars and infections.

Infectious granulomas are the cause of most benign lesions.

You have a greater risk for developing a solitary pulmonary nodule if you have:

• Tuberculosis or been exposed to TB
• Infectious lung diseases caused by fungus, such as:
  • Histoplasmosis
  • Coccidioidomycosis
  • Cryptococcosis
  • Aspergillosis

However, the above conditions makes it more likely that the solitary pulmonary nodule is noncancerous.

Young age, history of not smoking, calcium in the lesion, and small lesion size are factors associated with a noncancerous diagnosis.

Lung cancer is the most common cause of cancerous (malignant) pulmonary nodules.