Mastectomies require a sentinel lymph node biopsy. After general anesthesia, inject methylene blue (2 cc diluted with 2 cc saline) intradermally over the area of skin to be excised and massage into upper outer quadrant. Make curvilinear incision in axilla and do sentinel node biopsy, send for frozen section. If the frozen section is positive, then an axillary dissection can be performed prior to starting the reconstruction of choice. It is important to include all nodal tissue below the axillary vein, extending to the latissimus dorsi towards the tissue at the medial aspect of the pectoralis minor.

Create the incision that has been preoperatively determined on the affected breast. Raise skin flaps cephalad and caudad using skin hooks and Richardson retractors to create countertraction while pulling down on the breast tissue with your free hand. Typically scissors, scalpel, or electrocautery can be used to raise flap with long even strokes in parallel with the flap to minimize buttonholes or burns. Continually grasp flap between index and thumb to ensure even flap thickness. The flap should be 5- to 10-mm thick (7–8 mm ideal). Preserve parasternal and infraclavicular perforating vessels if possible, without compromising the oncological element of the procedure, to improve the viability of the skin flaps.

Remove all fibroglandular tissues within the borders of a simple mastectomy: the clavicle superiorly, inframammary crease inferiorly, latissimus dorsi laterally, and sternum medially. Dissect breast tissue off pectoralis major. The investing fascia of the pectoralis can be preserved if the tumor is small and the muscle is not involved, otherwise, excise the fascia and involved muscle. Separate the axillary tail from the pectoralis major and minor and the serratus anterior while sacrificing the lateral branches of the medial pectoral neurovascular bundle. Divide the breast tissue from the axillary contents with clamp and tie approach. If appropriate, continue to immediate reconstruction.