Ortho Dx: Painful tumor of the bone

A 42-year-old man presents with a 2-month history of groin pain on his right side. He denies injury or any known precipitating event. The pain is constant at rest and seems to be worse at night. He denies any history of cancer. Images from anteroposterior pelvis x-ray, coronal magnetic resonance imaging, and axial computed tomography are shown above. ...