Radiograph of the pelvis in an adult patient. No acute bony injury is demonstrated. Located in the left acetabulum close to the anterior inferior iliac spine there is an area of abnormal lucency with cortical thinning. Appearance is concerning for a potential neoplastic process. No pathological fracture is identified. No joint dislocation appreciated. Differential diagnosis includes a primary neoplasm but a metastasis is not excluded. The patient will require a staging CT scan of the chest abdomen pelvis in the first instance for further assessment.