Should I Be Worried?

Had CT w/contrast of abdomen during acute diverticulitis 1/06. 7mm noncalcified nodule found in left lower lobe. Follow up CT w/out contrast 4 month later, no change.
Acute diverticulitis again 4/09, CT w/ contrast shows bibasilar atelectasis and the aforementioned nodule is now 1.8 cm ground-glass nodular density.
I had stage zero breast cancer and bilateral mastectomies in 2003 and come from a very long line of cancer family members, but no lung cancers and have not smoked in 22 years. I am 56.  
What is bibasilar atelectasis? Should I be worried?  Lung doctor doesn't appear to be.

[carme]

Thanks for all your input!
Now that I have been through successful lower left lung lobectomy for bronchoalveolar carcinoma.

[julieben]

What were you diagnosed with?

Julie
SoCalif