There is a well-defined lytic lesion located centrally within the mid-diaphysis of the first metacarpal which has a thin sclerotic margin and central punctate calcfication. It is non-expansile and shows no evidence of cortical violation or overlying periosteal reaction.
There is also a large fat density mass within the thenar eminence, surrounding the first metacarpal and displacing the surrounding tissue. There are clear fat/tissue interfaces indicating little or no associated edema.
Lunotriquetral coalition is incidentally noted.