Background: Breast reconstruction is currently performed as standard practice. Methods: A prospective study was performed of patients after total mastectomy who underwent autologous breast reconstruction with fat grafting (FG) combined with internal tissue expansion between September 2015 and December 2020. The patients were classified into groups A to F depending on the steps of breast reconstruction. Groups A and B described patients with completed breast reconstruction with FG and expander removal, with or without nipple/areola complex reconstruction. C described patients during deflation of the expander combined with simultaneous FG. D described patients after expander implantation and refilling. E described patients after first FG, and F included patients who discontinued reconstruction with the described method and converted to reconstruction with a breast implant. Results: Among 22 treated patients‚ two were after first FG (9.09%‚ group E), two were after expander implantation and refilling (9.09%‚ group D), three were during deflation of the expander combined with simultaneous FG (13.63%‚ group C), and four (18.18%) had completed breast reconstruction-two (9.09%) without NAC reconstruction and symmetrization (group B) and two (9.09%) with completed breast reconstruction (group A). In 11 patients (50%), breast reconstruction was abandoned after expander implantation and one to three FG procedures (group F), converting to breast reconstruction with a breast implant. Conclusions: This study demonstrated successful breast reconstruction using FG and expander implantation. Breast reconstruction using this method is safe and enables possible abandonment at any treatment stage, as well as conversion to breast reconstruction with implants.