You must rule out axillary breast tissue when there are lumps under the armpit. Usually when you palpate axillary breast tissue you'll feel chords and it will feel firmer than fat. This is usually present under the hair bearing area of the axilla. The area next to the breast is usually fatty tissue and liposuction works in this area this is in the non-hair bearing area under the arm and to the side of the breast.
Axillary breast tissue should be excised because it is breast tissue and you can get a breast cancer in this tissue like any other breast tissue but it cannot be checked by mammogram. The fatty tissue to the side of the breast and the non-hair bearing area usually responds well to liposuction.