A calcified granuloma is an area of inflammation in tissue that has calcified over time until it has the same density as bone. The most common cause for a granuloma in the lungs is a fungal infection called histoplasmosis.
Calcified granulomas in the lung are not typically dangerous; they usually do not even cause signs or symptoms. Most granulomas in the lung are found accidentally during routine chest X-rays. Once a granuloma is found, additional imaging by X-ray or computerized tomography is needed to ensure that the spot on the X-ray is a granuloma and not a tumor, which look similar on scans. A granuloma in the lung does not specifically require treatment; however, if the granuloma was caused by a histoplasmosis infection, the infection is treated unless it has already cleared.
Histoplasmosis is an infection caused by inhaling airborne mold spores that originate in bird and bat droppings. Many of these infections occur in the upper Midwest and Ohio river valleys. Most people who acquire this infection never even know that they are sick as it does not cause symptoms, and a healthy immune system can quickly eliminate the fungus. A histoplasmosis infection can become very serious and require hospitalization in young children and adults with compromised immune systems.