Mirror syndrome resulting from metastatic congenital neuroblastoma.

Neuroblastoma is a tumor of the sympathetic ganglia and adrenal medulla that rarely metastasizes to the placenta. A 21-year-old gravida 3, para 1 at 28 weeks' gestation had an incidental finding of a 3.8-cm fetal renal mass on prenatal ultrasound. Within 1 week, the fetus developed hydrops and was delivered for nonreassuring fetal assessment. The mother developed mirror syndrome as manifested by hypertension, oliguria, and edema. The hydropic infant developed pulmonary hypertension, sepsis, and renal failure. On day of life 4, life support was discontinued. Pathological examination of the placenta revealed disseminated small round blue cells consistent with neuroblastoma. Metastasis of congenital neuroblastoma to the placenta is exceedingly rare, and cases discovered prenatally have resulted in significant maternal morbidity and 100% neonatal mortality.