Interestingly enough, I didn't have any cavities when first diagnosed. The diagnosis was a result of misdiagnosis of several bouts of pneumonia. My PCP finally referred me to a pulmonologist who then sent me to NJH. So I was relatively healthy then. It's only been within the past four years that cavities have developed. I had to pull out my NJH reports to see how big they are...and they aren't large at all. Two at this point...4 mm and 7mm. What I DO have are large nodules of mycobacterium...and portions of my airways that are so widened that some have collapsed. But my O2 is still good - 94 - 97 - so I don't have to use oxygen. I doubt this is very helpful, but one can only hope that by sharing it might shed a light for someone else.