A case of breast cancer: Suppression of lactation-related FDG uptake 2 days after cabergoline administration.

We present a case of a 35-year-old woman with breast cancer in lactation 3 months after childbirth, in which a lactation inhibitor was useful for 18F-FDG PET/CT examination. Via ultrasonography and biopsy with histopathology, we diagnosed the lesion in the upper region of the left breast as invasive ductal carcinoma. She stopped breastfeeding and was administered cabergoline to suppress lactation. Two days after the administration, 18F-FDG PET/CT revealed segmental uptake (10 cm in diameter) and no lactation-related uptakes. Dynamic MRI also revealed a segmental enhancement of the same size as 18F-FDG PET/CT. The lactation inhibitor was useful to delineate the extent of the lesion during the 18F-FDG PET/CT examination.