DIFFERENTIATION OF BENIGN AND MALIGNANT MUSCULOSKELETAL TUMORS - POTENTIAL PITFALLS WITH MR-IMAGING

Magnetic resonance (MR) imaging is the most sensitive and accurate ima ging technique for evaluation of musculoskeletal tumors. With increasi ng clinical experience, however, an overlap between the classic charac teristics of benign and malignant tumors is frequently observed, In a prospective analysis of 87 consecutive cases of musculoskeletal tumors , the malignancy of skeletal lesions was correctly assessed with MR im aging in 55% of the cases, In 39% of the cases, the malignancy of skel etal lesions was overestimated with MR imaging. Correlation with plain radiography is extremely important in such cases and would have resul ted in correct assessment of 73% of the skeletal lesions, For soft-tis sue lesions, a large variability is found in the benign versus maligna nt appearances of lesions on MR images, with poor correlation between classic benign characteristics and the benignity of the lesion (17% of cases), The exceptions are hemangiomas and lipomas, which have charac teristic appearances on MR images, Knowledge of potentially misleading appearances of musculoskeletal tumors on MR images allows more accura te diagnosis of such tumors.