Snapshot A 3-year-old girl is brought to the emergency room after her parents felt an abdominal mass during her bath. She is asymptomatic except for the mass, which is irregular, firm, and clearly crosses the midline, ruling out Wilms tumor. A week later, a biopsy of the mass comes back with rosette formation seen on histology and small round blue cells. Introduction Malignant tumor from cells of sympathetic nervous system login to view 3 more bullets Epidemiology login to view 1 more bullet Pathogenesis login to view 2 more bullets Genetics login to view 2 more bullets Associated conditions login to view 1 more bullet Presentation Symptoms login to view 2 more bullets Physical exam login to view 5 more bullets Evaluation Biopsy login to view 5 more bullets Urine login to view 2 more bullets Differential Diagnosis Wilms tumor Rhabdomyosarcoma Germ cell tumors Hepatoblastoma Treatment Surgical resection Prognosis, Prevention, and Complications Prognosis login to view 2 more bullets Complications login to view 1 more bullet