Bilateral Tibial Fibrous Dysplasia in a Pediatric Patient treated with Intramedullary Nailing.

Fibrous dysplasia is a benign developmental disorder of bone in which fibrous connective tissue containing abnormal bone with irregular trabeculae replaces normal cancellous bone. It may affect 1 (monostotic) or multiple bones (polyostotic). Polyostotic disease is the less common of the 2, occurring in only 20 to 25% of fibrous dysplasia patients and tending to affect those who are younger than 10 years of age; patients having this form tend to experience bone enlargement beyond normal skeletal maturation, which can cause pain, progressive damage, and increased risk of pathological fracture.

Bilateral Tibia Fibrous Dysplasia in a Pediatric Patient Treated with Intramedullary Nailing: A Case Report.

Fibrous dysplasia is benign developmental disorders of bone where normal lamellar cancellous bone is replaced with immature fibro-osseus tissue resulting in poorly formed trabeculae of immature woven bone. It may affect one (monostotic) or multiple bones (polyostotic). Polyostotic disease is less common, 20-25% of patients, mostly in children below 10 years old and tends to enlarge beyond bone maturation ration which can cause pain, progressive damage and higher tendency of pathological fractures.

Ewing sarcoma superimposed on a previous osteochondroma in multiple osteochondromatosis.

It has been reported that patients with hereditary multiple exostoses (called multiple osteochondromatosis by the World Health Organization) are at increased risk for malignant transformation of osteochondromas to secondary chondrosarcomas. A review of the literature found 14 cases showing transformation of osteochondromas into osteosarcomas; however, Ewing sarcoma has never been reported superimposed on an osteochondroma. This article presents the case of a boy who underwent biopsy of a previously existent osteochondroma for which the pathology report showed cytologic and immunohistochemical properties consistent with Ewing sarcoma.