When Should F-18 FDG PET/CT Be Used Instead of 68Ga-DOTA-Peptides to Investigate Metastatic Neuroendocrine Tumors?

A 67-year-old man, previously operated for a pancreatic neuroendocrine tumor (NET), had progressive increase of serum chromogranin A during follow-up. Sequential 68Ga-DOTA-NOC and F-18 FDG PET/CT were performed. 68Ga-DOTA-NOC imaging was negative, whereas F-18 FDG PET/CT showed 2 hypermetabolic hepatic lesions demonstrated at CT-guided biopsy as metastatic deposits from a high-grade (G3) aggressive NET. Despite the large consensus of SPECT or PET with radiolabeled somatostatin analogs as first choice in functional imaging for detecting NETs metastasis, F-18 FDG may occasionally be the right tracer to provide accurate diagnostic and prognostic information in aggressive G3 NET.