52 y/o F with recalled from screening for a left asymmetry. What is the most likely diagnosis?
Fat Necrosis
Saponification of local fat – benign inflammatory process
Related to direct trauma or surgery
Middle-aged women with pendulous breasts are more prone
Can evolve into an oil cyst (fine curvilinear calcification of the wall)
Mammo: Fat density [focal] asymmetry
US: Variable
Acute – hyperechoic due to edema
Subacute – ill-defined cystic lesion (anechoic) surrounded by edema (hyperechoic)
Late – round/oval mass with shadowing calcified walls
Related Radiology Article: Taboada JL, Stephens TW, Krishnamurthy S, Brandt KR, Whitman GJ. The many faces of fat necrosis in the breast. AJR Am J Roentgenol. 2009 Mar 1;192(3):815-25.