One of my close friends recently underwent minor breast augmentation (up like a half size). She was telling me about the procedure and explained that that the doctor gave her an injection of something into both breasts which somehow stimulates growth of natural breast tissue? I don't know much about physiology or biology, and I couldn't find anything about it online. She insisted that it's not any kind of implant, but rather it's basically just saline. However the information I've found online about saline injections is that they only provide enlargement for a day or two. Her results are permanent (well long term at least...she says that after child birth they may return to a sort of "normal").
What exactly is this method? It's not saline or silicon implants, nor is it fat injection--that much is clear. It also wasn't some sort of low-key cheap or experimental surgery. It was done by a respected plastic surgeon in a major US city. Has anyone heard of this type of work before and can explain it?