Fat necrosis is a noncancerous inflammatory condition thought to involve a vascular insult to adipose cells.1 This condition is most often encountered in the breast, abdomen, and extremities with a potential risk factor being obesity. The cause for fat necrosis in most cases is unknown, but common potential causes include blunt trauma, surgery, and radiotherapy. In cases of whole-breast irradiation, up to 30% of patients may develop fat necrosis, and up to 8% of patients present with clinical symptoms related to fat necrosis. Fat necrosis can progress, remain the same, or resolve. Fat necrosis can mimic breast cancer, both clinically and on imaging, especially in progressive cases associated with breast deformity.2–7
This article reviews the clinical, imaging, and pathologic features of fat necrosis of the breast, which will enable radiologists to better assess the clinical presentations and imaging appearances of fat necrosis of the breast on mammography, breast ultrasound, and breast MRI and more confidently suggest appropriate treatment.