Fat Necrosis in the Post-Surgical Breast: Dependence on Adjuvant Treatment and Morphology on Digital Mammography

Background: Fat necrosis is a common finding after trauma or surgery of the breast. There are various presentations on imaging and differentiation from malignancy can be challenging. Objectives: To analyze early signs of fat necrosis on postoperative mammograms after the excision of benign and malignant findings in accordance to modern adjuvant treatment. Patients and Methods: A retrospective analysis was performed as part of an audit. Mammograms of 39 patients, who underwent surgical excision of benign disease, and 81 patients with cancer surgery, were reviewed. Adjuvant therapy, such as radiotherapy, chemotherapy and hormonal treatment, was noted. Results: Mean patient age was 54.6 6.5 years in the benign and 59.8 7.8 years in the malignant group. Mean lesion size did not differ between the groups (P = 0.735). Development of fat necrosis on mammography follow-up was observed in 12.8% (5/39) of the patients in the benign and in 32.1% (26/81) of the patients in the malignant group (P = 0.024). Mean follow-up time until the first sign of fat necrosis was 2.6 years in the benign group and 2.0 years in the malignant group (P = 0.187). With radiation therapy hormonal treatment 25 of 75 patients (33.3%) developed fat necrosis. Hormonal treatment significantly influenced the development of fat necrosis in the malignant group (odds ratio [OR]: 0.231; P = 0.029). Four of 16 patients (25.0%) having radiation and chemotherapy developed fat necrosis. Conclusion: Fat necrosis development was observed significantly more often in patients after breast cancer surgery and modern adjuvant treatment compared to benign breast surgery. However, hormonal adjuvant treatment seemed to lower the chance of fat necrosis development.