title: Intraarticular epiphyseal osteoid osteoma of the distal femur.
abstract: A 9-year-old boy had pain in the medial side of the right knee with limited range of motion and limping. Roentgenography showed a small sclerotic shadow (8 X 8 mm2) in the medial femoral condyle, where bone scintigraphy revealed a high uptake area and angiography showed a nidus. Five months after initial presentation, en bloc excision was done through the posteromedial approach. Histological examination showed a network of osteoid trabeculae, differentiated osteoblasts, and multinucleated giant cells in this nidus, which were compatible with those of osteoid osteoma. Complete relief of pain was obtained at follow-up 1 year after the operation.
mesh_terms: D002648:Child; D004838:Epiphyses / Q000473:pathology; D005266:Femoral Neoplasms / Q000175:diagnosis / Q000473:pathology*; D005269:Femur / Q000473:pathology; D006801:Humans; D007717:Knee; D008297:Male; D010017:Osteoma, Osteoid / Q000175:diagnosis / Q000473:pathology*