Magnetic resonance imaging of musculoskeletal soft tissue masses.

The role of MR imaging in the evaluation of children with large, deep, or infiltrative soft tissue masses is to characterize and determine the extent of the lesion for treatment planning. There are a small number of soft tissue tumors with MR imaging appearances characteristic enough to allow a specific diagnosis, obviating biopsy. In the remaining cases with nonspecific imaging appearances, MR imaging is used for anatomic staging, but tissue sampling is still required for determining histology and grading.