A 37-year-old male patient complained right knee stiffness and right thigh numbness for several weeks. He did not have trauma or major surgery history. Due to large osteolytic lesion in right ilium and right femur revealed on planar X-ray examination, whole body bone scan was arranged to see if there was any abnormal uptake. Meanwhile, since extraosseous lesions were proved by KUB, MRI and CT scans, 210Tl tumor scan was then arranged. We incidentally found that after manipulation of above two scans, one add scan and two divided scans were rendered, indicating whole part of pseudotumor formation, most active part of pseudotumor and overuse hyperplasia of thigh muscles, respectively.