SUBPERIOSTEAL OSTEOID OSTEOMA - RADIOGRAPHIC AND PATHOLOGICAL MANIFESTATIONS

Objective. To demonstrate the radiologic and pathologic manifestations of osteoid osteoma arising beneath the periosteum, on the surface of the bone. Design. One hundred and sixty osteoid osteomas were seen ove r a 30-year period. The radiologic, pathologic and operative findings of those that were subperiosteal were reviewed. Patients. Eleven patie nts with subperiosteal osteoid osteoma were reviewed. The patients ran ged in age from 13 to 36 years with a mean of 24 years. Eight were mal e and three were female. Results and conclusion. Eleven subperiosteal lesions were studied. The reactive periostitis of four lesions was aty pical and misleading. Four lesions had features similar to the more co mmon intracortical variety. Three lesions occurring within the joint l ike other intra-articular lesions were barely seen on plain radiograph s. Bone scan and CT scan were virtually diagnostic. The histopathology of these lesions was also atypical though not misleading. In conclusi on, subperiosteal osteoid osteoma is a rare lesion with atypical radio graphic and histopathologic features. The unusual reactive periostitis seen in several extra-articular cases may suggest other diagnoses.