Osteochondromas are bone protuberances surrounded by a cartilage layer. They generally affect the extremities of the long bones in an immature skeleton and deform them. They usually occur singly, but a multiple form of presentation may be found. They have a very characteristic appearance and are easily diagnosed. However, an atypical site (in the axial skeleton) and/or malignant transformation of the lesion may sometimes make it difficult to identify osteochondromas immediately by means of radiographic examination. In these cases, imaging examinations that are more refined are necessary. Although osteochondromas do not directly affect these patients’ life expectancy, certain complications may occur, with varying degrees of severity.

INTRODUCTION:Identification of variables that determine the prognosis for osteosarcoma may enable stratification of patients into subgroups with better or worse risk of local recurrence, metastases and death due to the disease. Discovery of such prognostic factors would permit selection of a subgroup of at-risk patients, with the aim of improving the therapeutic effectiveness.OBJECTIVE:To identify prognostic factors related to local recurrence-free survival, metastasis-free survival and overall survival among patients with highly malignant primary osteosarcoma that was non-metastatic on diagnosis and had poor response to neoadjuvant chemotherapy.SAMPLE AND METHODS:Out of 45 patients admitted to a referral center in Brazil between 2000 and 2004, 24 were selected for this study.RESULTS:The adverse factors that influenced the risk of local recurrence and the overall survival in univariate analysis were histological subtype other than osteoblastic (p = 0.017) and tumor size greater than 15 cm (p = 0.048). In relation to metastasis-free survival, the non-osteoblastic subtype had a worse prognosis (p = 0.007). The association of histological subtype maintained its significance in multivariate analysis for all studied survival categories.CONCLUSIONS:Tumor size greater than 15 cm is an adverse factor for local recurrence-free survival and overall survival but did not influence metastasis-free survival. The osteosarcoma histological type is a significant independent predictor for local recurrence-free survival, metastasis-free survival and overall survival.

r e v b r a s o r t o p . 2 0 1 4;4 9(6):555-564 w w w . r b o . o r g . b r Artigo de Atualização