A 32-year-old man was seen with one-year history of nontraumatic right leg pain, which became usually worse at night. X-ray revealed a round circumscribed sclerosis in the anterior aspect of the tibia. 99m-Tc scanning demonstrated the increased activity around the nidus in the tibia. Thermogram also showed a hot spot at the same region with the 99m-Tc scanning.
Histological findings were charactrized by vascularized connective tissue, numerous irregular woven bone with osteoid, and a small number of giant cells like a osteoclast in the field.