What is the cost to evacuate a seroma from one breast? Any California PS who do needle aspirations?

Unfortunately there is no absolute answer to your question.  Your cost for revisionary surgery is at the discretion of the surgeon. Only you can answer what you feel is fair.  Personally I do not believe a surgeon should profit from revisionary work.  On the other hand, some sharing of the operating room costs can be a good compromise.  If your surgeon wants to do this at no cost to you then you have found not only a good doctor but a very compassionate and generous person too.  Good luck with the seroma. Needle aspiration may not be worth the risk if the seroma has been present longer than a week or two. The fluid isn't the problem, it's what is causing it.  If you do a needle aspiration your surgeon may want to send the fluid to the lab for evaluation.