About 3 weeks ago we took our 13 year old son to the ER because of complaints of pain when he took a breath. They diagnosed him with pleuracy, but they had also done an x-ray and said they happened to notice a spot or nodule in his right upper lung. They said it had nothing to do with his current condition of pleuracy, but advised us to go for a follow-up with our family doctor. Followed up with family Dr. and he ordered an additional xray about 2 weeks later. Just got those results and the spot had grown. They immediately got us in to go over results and ordered CBC and another blood test, a sputem culture and a TB test. They said they were going to treat it as a slow growing pneumonia and put him on a round of Zithromax and a shot of rofucin. Have to go in first thing Monday for all of the results. My question is I guess as a mom, i would like to know what is the most serious thing this could be?