- Osteoid osteoma is a small, painful, benign bone tumor that occurs most frequently during the first 3 decades of life (90% of patients are younger than 25 years).
- Osteoid osteoma is usually fewer than 2 cm in diameter, which distinguishes it from an osteoblastoma.
- Osteoid osteoma has a male predominance and a male-to-female ratio of at least 2:1.
- Most common location of osteoid osteoma is the proximal femur. Tumors in the tibia and femur account for 50% of occurrences, but virtually any bone can be affected.
- Typical symptom is local pain that is described as severe, sharp (knifelike), boring, typically worse at night, and typically relieved with salicylates.
 Imaging Findings
 Plain film
- A circular or ovoid lucent defect is seen in 75% of patients. This defect is usually smaller than 1.5 cm in diameter and is associated with a variable degree of cortical and endosteal sclerosis.
- CT allows for precise localization of the nidus.
- The nidus enhances with intravenous contrast.
- The nidus shows a variable degree of mineralization, which may be amorphous, punctate, ringlike or uniformly dens.
- Reactive sclerosis around the nidus varies from extremely dense to no reaction at all.
 See Also
 External Links
- Afshin Gangi, Houman Alizadeh, Lisa Wong, Xavier Buy, Jean-Louis Dietemann, and Catherine Roy. Osteoid Osteoma: Percutaneous Laser Ablation and Follow-up in 114 Patients. Radiology 2006 242: 293-301.
- Ali Nawaz Khan. E-medicine radiology article.