Osteoid osteoma: A pathology that is confused with ankylosing spondylitis.

Osteoid osteoma is a small and benign osteoblastic tumor seen typically in males aged below 25 years. Although it is rarely seen in the vertebrae, it should be considered in the differential diagnosis of spondyloarthropathies, especially for those which occur in young people, along with back and lumbar pain, which increases during the night. Early diagnosis is essential to alle-viate symptoms and prevent the risk of structural spinal deformities, such as scoliosis. Here, we describe the case of a 28-year-old man with vertebral osteoid osteoma that was misdiagnosed as ankylosing spondylitis and provide a detailed account of the radiological investigations.