OMG Faust - raises hand!!!! I have had such a cavity!!!
My MAC literally ate away an area of my left lung! And yes the MAC was hell bent on killling me. It is NOT a bug to mess around with. Run don't walk to the treatment they recommend for you.
I was immediately wisked away, referred to a thoracix surgeon and on the operating table within days of finding my large cavity. They performed a wedge resection, meaning rather just removing one lobe, both lobes were affected, they sliced away sections of both lobes leaving me as much functioning, good lung tissue as possible.
The recovery was long and hard. Since both lobes needed to be stitched up and wait to heal with 2 very large chest tubes about 2' long each coiled inside me. The tubes were very painful and I was on a morphine drip every 4 hours for a month. In the hospital a total of 5 weeks.
Surgery was followed up with 1 1/2 years of hideous regimin of antibiotics similar to TB treatment. But in the end I'm very glad I chose the surgery. It was a complete success and I have now testing negative for Mac since 2000. <img src="i/expressions/face-icon-small-happy.gif" border="0">
And I might add, that my cavity happened all very quickly in say a 4 month period between xrays. So it is very possible that is why yours didn't show up sooner. MAC can spread rapidly so don't hesitate if that's what you have. Get treatment my friend!!!