We report an unusual case of a solid-pseudopapillary pancreatic tumor (SPPT) with aggressive behavior that occurred in a 16-year-old male patient. ¹⁸F fluorodeoxyglucose PET/CT showed increased radiopharmaceutical uptake in a solid mass of the body of the pancreas, in several liver lesions, and in multiple peritoneal implants, corresponding to an SPPT with liver and peritoneal metastases, respectively. Based on PET/CT findings, the patient was referred to chemotherapy. In this unusual case of pediatric SPPT with aggressive behavior, ¹⁸F fluorodeoxyglucose PET/CT has been useful in staging the disease and in treatment planning.