Spots on Lungs

I have been suffering with severe allergies in the summer. Runny nose, watery itchy eyes, sore throat, drip and cough. I have also had a cat scan which showed spots on my lungs. They have been redoing the cat scans every 4 months and they have not seen a change in over 2 years. My last cat scan showed another spot. Now they want to biopsy. I am told it is not necessarily cancer. What else could it be?
I am a former smoker who quit over a year ago.
Thanks

[National Jewish Health]

Stability of the "spots" over a 2 year period strongly suggests a benign cause, even with the apparent development of another spot.  Without further information about the number and size of the spots, your age, your smoking history, the appearance of the spots and the new spot, we cannot provide an opinion on the need for a biopsy.  If the new spot closely resembles the old spots, size, shape, smoothness (or not) of borders etc., it is highly likely that the cause of the new spot is the same as the cause of the stable old spots, which have not changed in 2 years.

You should seek the opinion of a lung specialist, if you have not already.  Be sure to ask if he/she believes the "severe allergies" to be related or unrelated to the new spot.  Finally, you should ask the pulmonologist for an opinion on the likelihood of this new spot being a malignant tumor.

Good luck.