Imaging of benign and malignant soft tissue masses of the foot.

The foot is a relatively uncommon site of neoplastic and non-neoplastic soft tissue tumors. Although it contains a relatively small amount of somatic soft tissue elements, the foot is considerably rich in tendons, fasciae, retinaculae, and synovium. Corresponding to this distribution of soft tissue elements, some soft tissue lesions, such as giant cell tumor of tendon sheath, fibromatosis, and synovial sarcoma, are commonly seen in this location. Vascular tumors represent common soft tissue masses of the foot as well. Magnetic resonance imaging is the modality of choice in the assessment of soft tissue tumors. The presence of a suspected lesion can be confirmed and tumor margins can be defined accurately. In general, MRI does not provide histologic specificity, but considering some MR features may often help in correctly distinguishing benign from malignant lesions. In addition, characteristic features of the most common benign tumors (i.e., fibromatosis, cavernous hemangioma) and reactive processes of the foot (ganglion cyst, Morton's neuroma) often suggest a specific diagnosis.