A 10-year-old boy presented with a 3-day history of worsening abdominal pain, fever, emesis and melena. Abdominal ultrasound revealed a right upper quadrant mass that was confirmed by computed tomography angiogram (CTA), which showed an 8 cm well-defined retroperitoneal vascular mass. (123)Iodine metaiodobenzylguanidine ((123)MIBG) scan indicated uptake only in the abdominal mass. Subsequent biopsy revealed a paraganglioma that was treated with chemotherapy. This case represents an unusual presentation of a paraganglioma associated with gastrointestinal (GI) bleeding and highlights the utility of CTA and (123)MIBG in evaluation and treatment.