Nodules can be caused by infection, inflammation including Wegener's, and cancer. It is highly likely that any nodules found in a 36 year old, non-smoker will not be cancer. To know for sure a biopsy may need to be done. Some fungal Infections can result in nodules. This is
commonCommon cold in California, Arizona, and the Midwest, especially in the Ohio River Valley.
His pulmonologist told him that CT scans are taken in 10 mm slices. Since he was probably positioned slightly differently on the second one than the first one, this 6 mm nodule showed up because the slice the scanner took fell on it the second time and not on the first time (i.e. it was between slices).
He didn't seem concerned about this and wants him to have another in 6 months. My husband was very relieved.
I obviously don't know your history, and cannot obviously answer your question about diagnosis, but I wanted to let you know this information about how the CT scanner physicially worked so you would realize that where you're positioned can make a difference in what is seen. The doc also told him that they can take the slices a lot closer together, but this exposes the patient to a lot more radiation each time, so apparently they don't do this unless they have to.
Good luck.