Primary "xanthoma" of the bone is a rare lesion of unsettled histogenesis that may pose a diagnostic challenge owing to its wide range of differential diagnosis. Herein, we present a case of primary xanthoma of the right acromion in a middle aged woman who had no aberrant lipid metabolism or evidence of other pre-existing bone lesions. To our knowledge, this is the second reported case of a primary xanthoma involving the acromion in an adult.