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 most commonly in adrenal medulla and paraspinal region most common adrenal tumor in kids vs pheochromocytoma, which is most common in adults Epidemiology in < 4 years old Pathogenesis neural crest cell origin anywhere along sympathetic chain Genetics associated with amplification of N-Myc oncogene nuclear transcription factor Associated conditions opsoclonus myoclonus syndrome Presentation Symptoms abdominal distention abdominal pain Physical exam palpable firm and irregular mass crosses midline (vs Wilms tumor which is unilateral and smooth) may have diastolic hypertension opsoclonus (dancing eyes) – hallmark of disease myoclonus (dancing feet) – hallmark of disease Evaluation Biopsy histology Homer-Wright rosettes small round blue/purple cells Bombesin + stimulates neuroblastoma growth and expression of angiogenic markers Urine ↑ homovanillic acid (breakdown product of dopamine) ↑ vanillyl mandelic acid (breakdown product of norepinephrine and epinephrine) Differential Diagnosis Wilms tumor Rhabdomyosarcoma Germ cell tumors Hepatoblastoma Treatment Surgical resection Prognosis, Prevention, and Complications Prognosis younger patients with better prognosis (except for newborns) low n-myc associated with better prognosis Complications metastases to bone and skin