Breast (& Nipple-Areolar Complex)

Premenopausal women (and postmenopausal women on HRT) will often have mild and sometimes heterogeneous FDG uptake involving the breast parenchyma.  Generally, the denser the breast parenchyma, the more intense the FDG uptake.

Diffuse and relatively symmetric FDG uptake within both breasts is normal.

Focal breast uptake, however, should always be treated with suspicion, even if only mildly avid.

Fat Necrosis: 

Usually resulting from surgery, trauma or radiation therapy, fat necrosis can mimic a breast mass.  On CT, it typically appears as a round encapsulated region of fat density, which can be FDG-avid.  Associated peripheral calcification may be present. Its fat-equivalent density and a history of trauma, surgery or radiation therapy are the clues to this diagnosis.

Nipple-Areolar Complex: 

Mild to moderate FDG uptake involving the nipple-areolar complex is extremely common and is typically bilateral. It is considered normal in the absence of a corresponding CT abnormality.

Prostheses, Implants & Expanders:

Peripheral FDG uptake surrounding breast implants, tissue expanders and prostheses is a normal finding after surgery, even if intensely-avid. Such uptake slowly dissipates over time, with only minimal uptake remaining after 3-months.