Normalization of Liver Physiological Uptake as a Response Marker to Treatment in Prostate Cancer Liver Metastases Appearing as Photopenic on Baseline 18F-Fluorocholine PET/CT.

In a 54-year-old patient referred for 18F-fluorocholine (FCH) baseline PET/CT before chemotherapy for biopsy-proven liver metastases, FCH PET/CT demonstrated multiple hypodense hepatic lesions with no FCH uptake and 2 positive bone metastases. FCH PET/CT performed after 6 cycles of docetaxel demonstrated a near normalization of the physiological uptake in the area of the sterilized liver metastases, which was confirmed by a drop in prostate-specific antigen and a complete metabolic response in the bone metastases. The present case demonstrates a new pattern of response defined by a reverse phenomenon from photopenic to normal uptake in responding liver metastases.