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Lung diseases

Calcified Granuloma



i have had a cat scan which says i have a 8mm calcified granuloma in the lingula. my doctor has ordered a pet scan. is this normal


A granuloma is a scar that is left behind following certain types of lung infections. Infections that cause granulomas include histoplasmosis (very common) and tuberculosis (much less common). Granulomas can be found in about 25% of persons who live in the Midwestern United States. Granulomas show up as nodules on chest x-rays or CT scans. 
If a pulmonary nodule is completely calcified, then it almost certain that it is a benign granuloma. However, if a nodule is only partly calcified or if it is not calcified at all, then it could be a granuloma but could also be a small cancer. 
A PET scan is a test used to tell if a nodule is cancer or not. PET scans are only useful if a nodule is at least 8 mm in size. Usually a radiologist or a pulmonologist can look at an x-ray or a CT scan to determine if the calcification pattern of a nodule is sufficient to call it benign or whether further testing (such as a PET scan) is necessary to distinguish granulomas from cancers.

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Response by:

James N Allen, Jr, MD James N Allen, Jr, MD
Clinical Professor of Pulmonary, Allergy, Critical Care & Sleep Medicine
College of Medicine
The Ohio State University