Osteoid Osteoma and Osteoblastoma

An osteoid osteoma is a benign bone-forming tumor, which usually presents in childhood and adolescence and typically is characterized by extensive nocturnal pain. Regarding osseous tumors of the spine, characteristic morphology is encountered in osteoid osteoma and nonaggressive osteoblastomas (giant osteoid osteomas), and in these cases, radiological imaging can make a specific diagnosis, especially when the radiologist has chosen thin-sliced computed tomography (CT) as imaging modality of choice to establish the diagnosis in suspected osteoid osteoma. In osteoid osteoma, CT reveals the typical radiolucent nidus surrounded by a sclerotic reaction. Magnetic resonance imaging (MRI) typically demonstrates a nidal contrast enhancement and perifocal edema. Especially in spinal osteoid osteomas, the diagnosis is often delayed by more than 1 year. The radiologist plays a crucial role in the clinical pathway by “choosing wisely” the imaging approach, by narrowing the differential diagnosis list, and, when characteristic morphology is encountered, by establishing the diagnosis. Having shown excellent success rates, radiofrequency ablation has become the treatment of choice, which allows minimally invasive and precise destruction of nidal tumor tissue. By using thermal protection techniques and multiple ablation positions, successful therapy of perineural tumors and niduses with diameters of more than 2 cm (giant osteoid osteomas) are possible.