A rare presentation of osteoid osteoma in a rib and unexpected double density sign: A case report and review of literature

Osteoid osteoma (oo) is a relatively common skeletal neoplasm, frequently involves long bones. oo of rib is extremely rare, including 0.23-2% of oo cases. most of them arose in posterior arc, frequently in its head or neck and might lead to painful scoliosis. involvement of anterior aspect of a rib is extremely rare. skeletal scintigraphy is highly sensitive for detection of oo. “double density sign; a typical pattern in bone scintigraphy is usually seen in oo of cortical bones. the current study presents a case of 22-year-old man with oo in anterior arc of a rib, revealed double density sign on 99mtc-mdp scan