A Review on Fat Necrosis of the Breast: The Dilemma of Differential Diagnosis with Cancer

Fat necrosis is a benign inflammatory process which can involve adipose tissue anywhere in the body.Aprevious history of trauma or surgery may or may not be present. Information about the clinical and radiological appearance of this lesion is very important because it can mimic breast cancer. In this article, we review the features of fat necrosis in different imaging modalities including mammography, ultrasound, and magnetic resonance imaging (MRI), and compare them with histopathologic findings; then, we try to provide a logical approach for fat necrosis management. The appearance of fat necrosis at imaging is variable from definitely benign type to highly suspicious for malignancy. The specificity of mammography is higher than that of ultrasonography; therefore, for a definite diagnosis of fat necrosis, emphasis should be mainly based on mammography rather than ultrasonography. Finally, fat necrosis is not a common disease; however, regarding unusual and atypical findings in different imaging modalities, differentiation from a cancer may be difficult, especially in patients with a previous history of malignancy. Therefore, a multimodality approach is required for a definite diagnosis.