Figure 9a. Melanoma in a 35-year-old man. Axial T1- (a) and T2-weighted (b) images show a large mass in the right axilla (solid arrows in a) contiguous to and displacing the right brachial plexus (arrowhead in a). Note the subtle areas of increased T1 signal intensity within the mass that are characteristic of melanoma. Open arrow = subclavian artery.