Non-metastatic osteosarcoma of the extremities in children aged 5 years or younger

Background The occurrence of high‐grade osteosarcoma is rare in children aged 5 years or younger and only limited series or case reports have been described. Methods The records of patients aged 5 years or younger with non‐metastatic high‐grade osteosarcoma of the extremities treated with surgery and adjuvant or neo‐adjuvant chemotherapy at Rizzoli Institute between 1972 and 1999 were retrospectively evaluated in relation to gender, primary tumor site, histological subtype, surgical treatment, chemotherapy‐induced tumor necrosis, 5‐ and 10‐year event‐free survival (EFS), and rate of local recurrence. Data were compared to patients aged 6–40 years entered with the same diagnosis and over the same time interval. Results Data from 20 patients were collected. Comparing these data with those from 1,106 patients 6–40 years of age only two main differences resulted: the younger group showed a higher rate for fibroblastic subtype (P