Purpose: Osteosarcoma is a rare disease after the age of 40 years. Most malignant bone tumours at this age are secondary lesions and the primary tumours observed are generally chondrosarcomas. We report a small retrospective series to study the characteristic features and point out diagnostic difficultis as well as the prognosis in this age group.

Material and methods: We included in this series histologically proven osteosarcomas observed in patients over the age of 40 years who had been treated between 1990 and September 2002, excluding tumours occurring in patients with predisposing conditions (radiation, paget). The series included six women and nine men, mean age 54 years (41–79). Only three patients were over 60.

Results: During this same period, 59 osteosarcomas were treated. Diagnosis before 40 years corresponded to 25% of the cases reported at our interdisciplinary reunion. Three patients were referred after inadequate treatment, i.e. curettage-filling without diagnosis. Two others had undergone surgery for symptoms related to the osteosarcoma. Finally three patients had an erroneous or doubtful pathological diagnosis. There was no histological specificity or tumour localisation. The lower femur predominated. Ten patients had undergone neo-adjuvant chemotherapy with only two responders. Marginal surgery was achieved in three cases, intralesional surgery with immediate revision in one and large resection in ten. Six patients died from their disease (within two years of diagnosis) and one developed postoperative pulmonary embolism (46%). Two patients were living with active disease. Only six patients were living disease-free (40%). These included one patient with resected pulmonary metastasis and one patient who had experienced two episodes of locoregional recurrence which were operated (follow-up 12 and 8 months from last event). Four patients (26%) were in complete remission without any event since treatment (including two low-grade tumours).

Conclusion: Osteosarcoma after 40 years is, in our experience, more frequent than reported in the literature. In at least six of our patients (40%) this tumour was mis-diagnosed leading to non-optimal treatment. The prognosis is very poor with only 26% of the patients in complete remission without an event since treatment.