Osteoid osteoma presents in the 2nd and 3rd decades. It is slightly more common in males. The clinical history is of pain, often at night, which is relieved by Aspirin. If found in the spine, the most likely site is the pedicle.
Osteoid osteoma is a benign tumour of bone matrix.
Histologically its low density portion comprises osteoblasts and some fibrous tissue. The high density portion in the typical plain film image is bone reaction. Near the cortex, the lesion stimulates periosteal newbone. The lesion is often found with isotope bone scanning in those cases where the medullary location or neighbouring joints may not result in enough density to be diagnosed easily on the plain film. Various anatomic expressions of pathology.