Osteoid osteoma is characterized by an intracortical nidus with a variable amount of calcification, as well as cortical thickening, sclerosis, and bone marrow edema. The images of CT and MRI show exactly the same findings: central nidus seen best on CT, with bone marrow edema that is appreciated on the MRI.
These lesions are common in younger age group 20-40 years, and classically there is bone pain at night. Femur and tibial shafts are the common sites for occurrence.
