[Secondary head and neck osteosarcoma following treatment of undifferentiated nasopharyngeal neoplasms (UCNT)].

Secondary tumours after radio and/or chemotherapy are mainly of hematopoietic (acute non lymphoblastic leukemia, non-Hodgkin lymphoma) or soft tissue lineage previously described most frequently after breast cancer and Hodgkin disease treatment with radio and/or chemotherapy. We report two cases of classical osteosarcoma's observed 9 and 3 years after treatment for UCNT with combined radiotherapy and alkylant-based adjuvant chemotherapy in one case and exclusive loco-regional irradiation in the second case.