Developing (proliferating) - the original stage, which lasts about four a few months. At this time of gynecomastia it is reversible, after conservative therapy increased men's breast may go back to its normal size. Intermediate - lasts from 4 months to 1 1 year. At this time mature breast tissue. Go back to the old forms occur very hardly ever.Breast enlargement in men in the medical vocabulary is named gynecomastia. This is quite a common phenomenon (typical for all ages), the sources of which can end up being very different.