This is a 24-years old with a painful swelling over the left sterno-clavicular joint. The MRI clearly shows evidence of infection with an abscess. Aspiration of the joint is ideal to arrive at an answer. Tuberculosis commonly presents in this manner.
STIR coronal, T2 sagittal and T2 axial images show an erosive arthropathy in the left sterno-clavicular joint with an abscess that tracts superiorly and anteriorly.
This image shows post-contrast T1W coronal and axial images showing the same pathology.