Solitary pulmonary nodule (benign)

Definition:

A round or oval sharply circumscribed lung lesion up to 5 centimeters in diameter as seen in a chest X-ray.

Causes, incidence, and risk factors:

About 60% of all solitary pulmonary nodules are benign. Infectious granulomas (granular tumors) are the cause of most benign lesions, but primary lung cancer is the cause of 75% of all malignant solitary pulmonary lesions. Young age, absence of symptoms, and small size of the lesion are factors favoring a benign diagnosis. A history of pulmonary infection from Histoplasmosis, Coccidioidomycosis, or tuberculosis is a predisposing factor. The incidence is 2 out of 1,000 people.