Maintenance Phase Starting approximately 3 months following stem cell transplant subjects will receive six monthly treatments with 13-cis-retinoic acid. 13-cis retinoic acid is a drug closely related to vitamin A and has been shown to help stop the multiplication of any remaining neuroblastoma cells in the body. This drug will be taken 2 times a day by mouth for 14 days and then not take it for the following 14 days. This 28-day cycle will be repeated 6 times.