Abstract
Desmoid tumors are rare locally aggressive myelodysplastic tumors that are usually abdominally based. They account for 0.2% of breast tumors. Certain factors like prior surgery, familial adenomatous polyposis, pregnancy, and high estrogen states are associated with chest wall desmoid tumor occurrence. We present a patient with a history of intraductal carcinoma of the left breast who underwent mastectomy with implant-based reconstruction who had a desmoid tumor of the breast detected during workup for cardiac transplantation for chemotherapy-induced heart failure. The tumor was originally thought to be recurrent breast cancer during workup with imaging obscured by the implant. Excisional biopsy demonstrated a desmoid tumor with a positive deep margin requiring rib resection, synthetic mesh, and pectoralis major flap reconstruction. Breast desmoid tumors are reactive malignancies that have been diagnosed after prior breast implant surgery but without an established risk associated with breast implants. Excision with microscopically negative margins and chest wall reconstruction when indicated is the current established treatment protocol; however, recent paradigm shifts include "watchful waiting" and medical management among treatment strategies.