Colloidal cysts , calcification and hypodense nodule of thyroid - 1264164

I did search for something about the issue/topic that I am posting currently.. my Mom's adeno stage 3A lung cancer case started with an X-ray in May 2012 for a knee surgery that she was going to have. Anyway...it wasn't officially dx'ed until July 2012. She did have the ULL removed in Aug. '12 followed by five full rounds of carbo/paclitaxel , and concurrent (25) rounds of IMRT and (10) rounds of proton radiation. She has been receiving (so far) no evidence of recurrence and or metastic CT scans. Her PCP just ordered an ultrasound of her thyroid due to her TSH level indicated hypothyroidism... a numerical value of 6.42 if I remember correctly. Well...she has her (3) month CT follow up scan on 06/23/14...if all clear she will go to six month scans.. the questions we have now are due to some of the findings we just learned today. The PCP's nurse called this afternoon but did not have and or read the complete report obviously over the phone...she stated that there were colloidal cysts indicated, some calcification and there was a hypodense nodule indicated. My Mother did inform me the first CT she had during her initial work-up indicated a hypodense nodule..so... I know you normally do not speculate and or will not but any guidance on this will be extremely helpful. I've been searching the entire night tonight as I am worried. I've read what it might and or might not be..,it is just driving me insane. I am so very sorry for acting somewhat irrational as I know that it is best to be calm and clear thinking. Thank you so much for any help, information you may be able to provide.