False Positive Findings on 18F-MFBG PET/CT Attributable to Benign Neural Differentiation in a Pediatric Patient With Neuroblastoma

An 18F-MFBG PET/CT scan was performed in a 5-year-old girl diagnosed with high-risk neuroblastoma to further characterize indeterminate lesions previously identified on 123I-MIBG SPECT/CT. She was enrolled in our clinical trial. Moderate 18F-MFBG uptake was observed in pelvic lymph nodes and the left third sacral foramen. Histopathologic examination following surgical resection revealed mature ganglion cells embedded within Schwannian stroma in both lesions-findings consistent with benign neural differentiation, rather than residual or recurrent neuroblastoma. This case illustrates that false-positive 18F-MFBG PET/CT findings in pediatric neuroblastoma may arise from tracer accumulation associated with neural maturation.