Bone Marrow Activation After Chemotherapy Presenting as Diffuse Skeletal Uptake on F-18-Fluorocholine PET/CT

Diffuse F-18-FDG skeletal uptake due to chemotherapy-induced bone marrow activation is well documented, whereas it has never been reported with F-18-fluorocholine. We described a patient with pelvic recurrence of prostate cancer at F-18-fluorocholine PET/CT. A second PET/CT after docetaxel showed minimal residual activity in pelvis, but it revealed diffuse, intense F-18-fluorocholine skeletal uptake. Considering biochemical and metabolic response and absence of morphologically suspected bone lesions, skeletal hyperactivity was interpreted as chemotherapy-related bone marrow rebound rather than diffuse metastatic involvement, as confirmed by its resolution after treatment ended. The occurrence of such F-18-fluorocholine pattern should be considered to avoid imaging misinterpretation.