RATIONALE: Radioactive drugs, such as iodine I 131 metaiodobenzylguanidine, may carry radiation directly to tumor cells and not harm normal cells. Drugs used in chemotherapy, such as carboplatin, etoposide, and melphalan, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. An autologous peripheral stem cell or bone marrow transplant may be able to replace blood-forming cells that were destroyed by chemotherapy and radiation therapy. Giving iodine I 131 metaiodobenzylguanidine and combination chemotherapy with an autologous peripheral stem cell or bone marrow transplant may allow more chemotherapy to be given so that more tumor cells are killed. Giving radiation therapy after an autologous peripheral stem cell or bone marrow transplant may kill any remaining tumor cells.