Osteoid osteoma is one of the most common benign tumors in bone and constitutes about 10% of all benign bone tumors. Osteoid osteoma is most common in 10-30 years of age and is 2-3 times more common in males than females. It can occur any bone in the body, but the most common sites are the edge (cortex) of the leg bones. In about 15% of cases, the tumor is located in the spine. In this cases, the back (posterior) part of the spine is usually involved.
How is it diagnosed?
Pain is the most common finding in osteoid osteoma. Pain is more at night and dramatically decreases with drugs that reduce prostaglandin synthesis, such as acetyl salicylic acid. In the examinations performed upon these complaints, most osteoid osteomas can be diagnosed based on typical imaging findings and no biopsy is needed.
Imaging findings of osteoid osteoma are very typical. The inner part of the tumor resembles a bird's nest, which is usually called a nidus. Pathologically, this area is vessel-rich, and thus, it can be easily detected with angiography and bone scintigraphy. Around the nidus, there is an intense bone reaction. This typical view of the nidus and surrounding dense bone tissue is best seen on tomography and MRI and is considered specific for osteoid osteoma. If the patient's age and clinical findings support the diagnosis, a biopsy is not necessary and treatment can be performed directly.
How is it treated?
Classical treatment is surgery and is still in use today. Especially if there is doubt about the diagnosis, surgery may provide both pathological diagnosis and treatment. However, in the majority of patients, typical imaging findings and clinical findings are present and there is no doubt in the diagnosis.
Currently, the preferred treatment modality for osteoid osteoma is radiofrequency ablation. In radiofrequency ablation, a thin needle is inserted into the tumor and both tumor is destroyed by heat and the pain is eliminated. The procedure is done under local anesthesia and CT guidance, without any incision or suture. After treatment, the patient can usually be discharged on the same day.
Radiofrequency ablation therapy has been widely used in osteoid osteoma over the last 15 years. The success of the procedure is at least as high as surgical treatment, and the side effects such as bleeding and infection are much less because it does not require surgery. The duration of hospital stay and return to normal life is shorter. Due to these advantages, radiofrequency ablation is now considered the first choice in the treatment of osteoid osteoma. Surgical operation is preferred in a small patient group where radiofrequency ablation cannot be performed technically.
Interventional oncology in cancer management
Prof Saim Yilmaz, MD