Hepatic Superscan Secondary to Neuroblastoma Hepatic Metastases: Correlative 18F-FDG PET/CT and 123I-MIBG SPECT/CT Findings

A 4-year-old girl presented with persistent fever and an abdominal mass detected on ultrasound. 18F-FDG PET/CT revealed peripheral hypermetabolism with central photopenia in the abdominal lesion, diffuse hepatic 18F-FDG uptake, and hepatomegaly, consistent with a hepatic superscan. Biopsy confirmed neuroblastoma metastases to the liver and bone marrow (stage IV). Postchemotherapy 123I-MIBG SPECT/CT demonstrated absent lesion uptake but marked diffuse hepatic tracer accumulation with heterogeneous parenchymal density, fulfilling criteria for a hepatic superscan on MIBG imaging. This case illustrates dual-tracer hepatic superscans in neuroblastoma, which represents an uncommon clinical presentation.