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. There are limited reports of bilateral involvement in fibrous dysplasia, with said involvement presenting most frequently in early childhood. We describe the rare case of an adolescent presenting with bilateral fibrous dysplasia in the tibial diaphysis (in the exact same location) that was successfully treated with bilateral intramedullary nailing of both tibias.

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.(1) We report a case of polyostotic fibrous dysplasia present on bilateral tibia diaphysis. Patient presented with bilateral leg pain on examination and imaging showed bilateral tibia lytic lesion. Management consisted of reaming and intramedullary nailing on bilateral tibia after which patient presented without pain and radiographs showing no evidence of lesion. Tibia x-rays demonstrated exuberant cortical intramedullary bone formation with disappearance of the scalloped osteolytic lesions on the inner wall of tibial cortex. Clinically the patient's symptoms disappeared giving the opportunity to return to contact sports without limitation.

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. A 13-year-old boy with hereditary multiple exostoses (multiple osteochondromatosis) presented to an orthopedic clinic because of waxing and waning pain superficial to a previous osteochondroma on the lateral aspect of the right leg, below the knee, of 1 month's duration. On examination, inflammation was noted over a bony mass associated with tenderness to palpation of the affected area. There was no evidence of penetrating injury or trauma, and the patient reported no constitutional symptoms, including fever. Radiographs showed marked osteolysis and signs of periosteal reaction. Magnetic resonance imaging showed evidence of cortical bone erosion and extension of the mass into soft tissue. Malignant transformation was suspected, and the patient underwent biopsy. The pathology findings were consistent with Ewing sarcoma. The highly uncommon presentation of this malignancy must serve as a red flag to other physicians who treat patients with hereditary multiple exostoses. Ewing sarcoma tends to be of higher grade and have a worse prognosis than other malignancies that are more commonly seen in these patients.