MR-IMAGING ASSESSMENT OF JUXTA CORTICAL EDEMA IN OSTEOID OSTEOMA IN 28 PATIENTS

Osteoid osteoma (OO) is a benign skeletal neoplasm. Twenty-eight patie nts with proven OO were studied with MRI regarding soft tissue involve ment which was diagnosed when high proton-density and T2-weighted sign al intensity and low signal intensity on T1-weighted images were found close to bone. Most tumors were located in the femur and tibia, 6 cas es diaphyseal, 12 metaphyso-diaphyseal, and 10 epiphyseal. In relation to the cortex, 15 were located centrally or in its outer margin. Soft tissue involve ment was found in 15 patients (53.6 %). A statistical relationship was found between soft tissue involvement and the tumors location with regard to the cortex, being more frequent in peripherall y located tumors. Therefore, soft tissue involvement is a frequent fin ding in peripherally located OO.