A woman with colon cancer underwent FDG PET/CT. Images demonstrated an FDG-avid lytic defect in the posterosuperior right humeral head, without other suspicious lesions. Because it is rare for bone to be the first metastatic site in patients with colon cancer, additional clinical history was sought. The patient experienced chronic right-shoulder anterior dislocations. The diagnosis of Hill-Sachs lesion was made. A Hill-Sachs lesion is a depression in the posterosuperior aspect of the humeral head caused by impaction of the humeral head against the anterior scapular glenoid during anterior shoulder dislocation. FDG-avid Hill-Sachs lesions must be distinguished from malignancy.