Bone and Lymph Node Flare to Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer on 18F–Prostate-Specific Membrane Antigen PET/CT With Decreasing Prostate-Specific Antigen of 0.7 ng/mL

A 72-year-old man with prostate cancer was found to have prostate-specific membrane antigen (PSMA)-avid oligometastasis on initial staging with 18F-DCFPyL PET/CT. Meanwhile, his prostate-specific antigen was 10.0 ng/mL, and testosterone level was 381 ng/dL. Six weeks after initiation of treatment on androgen deprivation therapy plus abiraterone, his restaging 18F-DCFPyL PET/CT showed decreased PSMA uptake in primary prostate lesion, but increased uptake in bone and lymph node metastases, whereas his prostate-specific antigen decreased to 0.7 ng/mL, and testosterone level was <3 ng/dL. This case illustrates hormone-sensitive metastatic bone and lymph node flare on 18F-PSMA PET/CT.