Prenatally detected thoracic neuroblastoma.

Neuroblastoma is the most common pediatric extracranial solid tumor derived from primitive neural crest cells of the sympathetic nervous system. Although one-fifths of all neuroblastomas occurs within the thorax, thoracic neuroblastomas detected in fetus have been rarely reported. We report a case of fetal thoracic neuroblastoma with massive pleural effusion detected with prenatal ultrasonography. A 34-year-old Korean second-gravida was referred to our hospital at 30 weeks of gestation for evaluation, after the right lung mass found in the fetus. Approximately 3 cm, well-defined, hyperechoic mass was found in the right thorax with right pleural effusion, with the initial suspicion of teratoma. However, as mass continued to grow with deteriorating pleural effusion and fetal hydrops, the mass was considered malignant after 3 weeks. After a cesarean delivery, an approximately 4 cm mass with peripheral calcification and hemothorax was found on neonatal ultrasonography. Neuroblastoma was diagnosed on excision biopsy.