A 10-year-old boy presented with progressive swelling in the dorsolateral region of the right foot. He had had the symptoms for 3 years. He could recall no history of trauma. Physical examination showed a healthy patient with a tender mass on the dorsolateral region of the right foot measuring 3 cm/4 in diameter. The overlying skin was intact. There was neither tenosynovitis nor oedema. A radiograph of the right foot showed an eccentric lytic lesion of the cortex and the medullary space in the diaphysis of the fifth metatarsal with sclerotic margins (Figure 1). CT showed geodes with reactive sclerosis and soft tissue swelling without collection (Figure 2). The biopsy specimen revealed epithelio-gigantocellulary granuloma without caseous necrosis. He had a normal white-blood-cell count, a normal C-reactive protein level, and an erythrocyte sedimentation rate of 21 mm/hr. Tuberculosis research was negative (tuberculin skin test, sputum examination, and standard thoracic X-ray). Because of the suspicion of an osteolytic tumor, an open biopsy was performed. The cortex was found to be destroyed and replaced by granulation tissue. A thorn was found and removed. Histologically, chronic granulation tissue was confirmed. Six months after operation, radiographs show that the bone lesion was resolved, and remodeling occurred.