Breast reconstruction may be performed after mastectomy, to rebuild injured or congenitally deformed breasts, or as part of gender reassignment surgery. As part of the reconstruction process, a breast tissue expander may be used to stretch the patient's tissue for insertion of an implant or the patient's own tissue. Tissue expanders are like thick-walled silicone balloons, come in different sizes and shapes, and may have a smooth or textured outer surface. They are implanted under the breast skin, tissue, or chest muscle, and are regulated by the FDA as medical devices. In immediate reconstruction, the expander is inserted immediately following mastectomy. For patients who choose delayed reconstruction, the expander is implanted in a separate surgery months or years later.
In surgical practice, for the reconstruction of a breast, the tissue expander device is a temporary breast prosthesis used to form and establish an implant pocket for the future permanent breast implant. For the correction of male breast defects and deformities, the pectoral implant is the breast prosthesis used for the reconstruction and the aesthetic repair of a man's chest wall (see: gynecomastia and mastopexy).
The current lifetime risk of BIA-ALCL in the U.S. is unknown, but estimates have ranged between estimated to be between 1 in 70,000 to 1 in 500,000 women with breast implants according to MD Anderson. Certain geographic locations have demonstrated variable risks. For instance, a December 2016 update from the Therapeutic Goods Administration of Australia and New Zealand reported a risk of 1:1,000 to 1:10,000 for textured implants.". To date (2017), there has not been a case of BIAL reported where the patient had only implantation of smooth shell breast implants or a textured tissue expander that was exchanged for a smooth implant. The paucity of cases reported in Asian populations has raised the possibility that there may be a range of genetic susceptibility to the phenomena, or alternatively merely reflect differences in how cases are identified and reported.