[Second tumors in pediatric oncologic patients. Report of 5 cases].

The dramatic progress observed in the survival of children treated for cancer in the last two decades due to the use of aggressive chemotherapy and radiotherapy has brought an increased incidence of second malignant tumors. Five clinical cases of second malignant neoplasms after a period of six months to seventeen years after diagnosis are presented. The second tumors observed were: one patient with malignant fibrous histiocytoma of the orbit after treatment bilateral retinoblastoma; one patient with multifocal osteosarcoma after cerebelli medullo-blastoma; one patient with Ewing's sarcoma of the fibula after neuroblastoma of the adrenal gland; one case of carcinoma of the thyroid gland after osteosarcoma of the femur and one patient with acute lymphoblastic leukemia after been treated of osteosarcoma of the femur. The genetic, immunologic and therapeutic risk factors are reviewed and analyzed.