A calcified granuloma often occurs in a lung as the body’s response to an infection. A granuloma is a small area of infection. Most calcified granulomas are discovered during a chest X-ray for another purpose and do not require follow-up care, according to Mayo Clinic.
In the United States, histoplasmosis, a fungal infection, is the most common cause of calcified granulomas. People who spend time in the upper Midwest or the Ohio Valley are at greatest risk for developing this type of histoplasmosis, states Mayo Clinic. After the infection, it is often years before a health care professional discovers the calcified granuloma because it causes no symptoms.
Before granulomas calcify, they look similar to cancer on an X-ray even though they are noncancerous, explains Mayo Clinic. Once the granuloma calcifies, it takes on the density of bone, making it much clearer on the X-ray. Doctors sometimes order computerized tomography scans to distinguish between uncalcified granulomas and cancer.
Singular calcified nodes are common in most people over age 50, notes the University of Virginia Health Sciences Center Department of Radiology. If these nodes are less than 4 centimeters in diameter and the person has no other risk factors for lung disease, the nodes do not require follow-up care. Patients with a past history of malignancy or who smoke should have a follow-up X-ray in a year to monitor calcified nodes of this size.