Fat necrosis

Fat necrosis is a benign breast lesion which can radiologically, clinically and histologically (especially on frozen sections) simulate malignancy. Only a minority of patients report a history of trauma.

FNA specimens show necrotic and degenerating adipocytes with amorphous debris, inflammatory cells (neutrophils, plasma cells, lymphocytes) and numerous lipid-laden macrophages (lipophages). Multinucleated foreign body-type macrophages and fibroblasts can also be present.