Figure 1. A 43-year-old female breast cancer patient scheduled to undergo adjuvant chemotherapy.

We detected a mass in left breast (C. CT imaging), with a maximum diameter of 3.2cm. The tumor was FDG-avid with SUVmax of 8.99 (A. FDG PET/CT), but no obvious FES uptake was noted (B, D. FES PET/CT, SUVmax=1.1). After 4 cycles of NAC, the patient had mastectomy and the pathology showed it was grade A.