Clinical and Radiographic Features of Phalangeal Osteoid Osteoma

Osteoid osteoma is a benign osteoblastic tumor of unknown origin. It usually affects children, adolescents and young adults showing a strong male predominance. The tumor has a predilection for the metaphysis or diaphysis of long bones of the lower limbs but it may occur anywhere in the skeleton. It typically consists of a well-demarcated radiolucent rarefied area of bone-forming and prostaglandin-secreting nidus, occupying the midcortex, which is surrounded by an extensive fusiform reactive sclerotic host bone. Reactive sclerosis is usually more pronounced in children. The lesion may also be found in the medulla (spongiosa) of bone. In the cortical presentation, it may rarely occupy the endosteal or subperiosteal surface of the cortex. Intramedullary tumors are usually surrounded by a thin rim of reactive sclerosis and may frequently be periarticular or intraarticular, presenting with synovitis and joint effusion [1 10].