Fenretinide in Treating Children With Solid Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed malignant solid tumor that is refractory to conventional therapy or recurrent neuroblastoma treated with myeloablative therapy and autologous stem cell transplant in second complete or partial response * Bone marrow metastases with granulocytopenia, anemia, and/or thrombocytopenia are eligible PATIENT CHARACTERISTICS: * Age: Under 21 at diagnosis * Performance status: CCG 0-2 * Life expectancy: At least 2 months * Absolute neutrophil count at least 750/mm3 * Platelet count at least 50,000/mm3 * Hemoglobin at least 7.0 g/dL * Bilirubin no greater than 1.5 mg/dL * SGOT and SGPT less than 2.5 times normal * Creatinine no greater than 1.5 g/dL OR creatinine clearance at least 50 mL/min OR radioisotope GFR at least 50 mL/min * Seizure disorders controlled with anticonvulsants allowed * No CNS toxicity greater than grade 2 * Not pregnant * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: * At least 1 month since prior autologous stem cell transplantation * No prior allogeneic transplantation * At least 2 weeks since prior chemotherapy (4 weeks for nitrosourea) and recovered * No other concurrent chemotherapy * No concurrent immunomodulating agents (including steroids) * Concurrent corticosteroid therapy for increased intracranial pressure allowed * Concurrent dexamethasone for CNS tumor allowed * At least 2 weeks since prior radiotherapy * Concurrent radiotherapy to localized lesions allowed * At least 2 weeks since prior retinoids Prior isotretinoin or 9-cis-retinoic acid allowed