What is the absolute flattest breast reduction I can get without transitioning to male?

You raise many more questions with your basic question. Are you a female to male transgender patient? Or female who considers herself (themself) gender queer or gender neutral who simply wants no breasts? Do you wish to retain female nipples and large(r) feminine areolas? If your breasts are large and pendulous (do you bind?) Do you need skin reduction incisions? Or will keyhole incisions suffice? Incision patterns differ with gender identification, as female reduction scars look weird on a masculine chest.Are you really seeking transgender mastectomies but are hoping for insurance coverage for your top surgery? Or do you simply want your breasts removed for other (non-gender related) reasons? "Absolute flattest" is "no breasts. That can either be masculine (if done properly), or still distinctly female with no breasts (nipples on chest skin) and obviously without feminine breast form and shape--what some of my breast augmentation patients call "raisins on a plate."I would be most happy to speak with you personally, but would need much more information (including photos or personal examination) before I (or anyone else here) can offer appropriate advice. Please feel free to contact me. Best wishes! Dr. Tholen

If your goal is to completely lose all your breast tissue this is often a better answer and requires slightly different thinking when it comes to scars, recovery, etc...

A breast reduction can take you a small as you wish. This is something that she will discuss with your plastic surgeon.

Yes, it is possible to reduce the breasts size very significantly.   Sometimes  when patients want "the smallest size possible”  the reduction should be done in 2 stages.  The concern with the amount of tissue removed is related to blood flow to the remaining tissue;  if too much tissue is removed in one operation the blood flow to the remaining tissue (including nipple/areola)  may be compromised.   Part of the tissue that is left in place is called the “pedicle"; this segment of tissue is responsible for delivering the blood supply to the nipple/areola tissue. If the pedicle is made too small (in the effort to reduce the breasts as much as possible)  then patient will likely have problems with tissue survival.  Doing the procedure in more than one stage allows the tissues to  acclimate to the surgically decreased blood flow before  further tissue removal (and potentially further decreased blood flow)  occurs ( with the 2nd stage operation).The other concern with overly aggressive breast reduction surgery is patient dissatisfaction  afterwards.  It is not unusual for patients who have lived with very large breasts to want to have as much as possible removed. Care must be taken to be judicious in this removal to avoid an outcome where the breasts  are too small in relation (proportionately) to the patient's other body parts.  Again, it is not uncommon, for patients'  breasts to become smaller ( after the breast reduction procedure) with time and/or weight loss-  breast augmentation may become necessary to achieve the patient size goals.It will behoove you to seek consultation in person with a well experienced board-certified plastic surgeons.I  hope this, and the attached link, helps.

There are limits to how small a breast can be made based upon your anatomy.  There are various techniques available that will allow the surgeon to make the breast quite small.