Lung 3mm nodule means that in the lung ct examination found in the size of 3mm increased density of the lung shadow, mostly belong to benign lesions, so do not worry too much. 3mm lung nodules benign possibility, may be from the past long-term chronic lung inflammation did not get perfect treatment of the formation of inflammatory nodules; may also be once inadvertently chest violent collision led to local lung contusion, so that the lung tissue localized inflammation exudate or hemorrhage, failed to completely absorb the eventual formation of nodules. Lung 3mm nodules are more likely to be benign lesions, but malignant can not be completely ruled out, the need for regular review, so as to detect abnormalities in a timely manner after timely treatment, to avoid delays in the condition.