HD Melphalan and SCT in Patients With IGDD or LCDD

RATIONALE: Giving chemotherapy before a stem cell transplant stops the growth of cancer cells by stopping them from dividing or killing them. Giving colony-stimulating factors, such as G-CSF, and certain chemotherapy drugs, helps stem cells move from the bone marrow to the blood so they can be collected and stored. Chemotherapy is then given to prepare the bone marrow for the stem cell transplant. The stem cells are then returned to the patient to replace the blood-forming cells that were destroyed by the chemotherapy. PURPOSE: This phase II trial is studying the side effects of high-dose melphalan given together with stem cell transplant and to see how well it works in treating patients with immunoglobulin deposition disease or light-chain deposition disease.