99mTc-methylene diphosphonate single-photon emission computed tomography/computed tomography improves the diagnostic accuracy of osteoid osteoma

Osteoid Osteoma: An Updated Review of Epidemiology, Pathogenesis, Clinical Presentation, Radiological Features, and Treatment Option

Osteoid osteoma, the third most common benign bone tumor, usually occurs in the cortex of long bones. It consists of a radiolucent nidus surrounded by reactive osteosclerosis. Generally, osteoid osteoma affects young males. Nocturnal pain that eases with salicylates or nonsteroidal anti-inflammatory drugs (NSAID) is the typical clinical presentation. Sometimes, it remains undiagnosed for a long time. Plain radiography and computed tomography are usually sufficient for the diagnosis of osteoid osteoma. Initial treatment includes salicylates and NSAID because the tumor often regresses spontaneously over 2-6 years. Surgical treatment is indicated in case of unresponsive pain to medical therapy, no tolerance of prolonged NSAID therapy due to side effects, and no willingness to activity limitations. Nowadays, minimally invasive techniques have replaced open surgery and are considered the gold standard of surgical treatment. Although cryoablation seems superior in terms of the nerve damage and immunotherapy effect, radiofrequency ablation is the preferred technique.

Osteoid osteoma: multimodality imaging with focus on hybrid imaging

Osteoid osteoma is a painful, benign, osteoblastic lesion that occurs in younger patients and affects the extremities or the axial skeleton. While plain film findings may suggest the diagnosis, in complex anatomical regions such as the spine, pelvis, wrist and foot advanced imaging modalities are often required. A typical nidus surrounded by sclerosis or cortical thickening characterizes osteoid osteoma on plain radiography and CT. MR is the cross-sectional imaging modality of choice for most musculoskeletal disorders. Unfortunately, extensive accompanying bone marrow oedema, soft-tissue alterations, difficulty detecting the nidus, and lesion locations close to a joint (with reactive arthritis) may make a confident diagnosis of osteoid osteoma by MR imaging difficult. Hybrid imaging with bone-seeking tracers such as SPECT/CT with ^99mTc-labelled bisphosphonates or PET/CT with ¹⁸F-labelled sodium fluoride (¹⁸F-NaF) combines high radionuclide uptake with morphological details and provides accurate diagnosis of osteoid osteoma and additional information for treatment planning. FDG is not the recommended PET tracer because osteoid osteoma is normally FDG-negative, although some osteoid osteomas may show increased FDG uptake. Osteoblastoma, Brodie's abscess and stress fractures may mimic osteoid osteoma on imaging and clinical presentation. Once identified as the pain generator, destruction of the osteoid osteoma nidus by ablation or resection techniques usually leads to complete healing. Image-guided drill excision and radiofrequency ablation are widely used interventions. We review the presentation of osteoid osteoma across all imaging modalities, with special focus on hybrid imaging techniques.

Intra-Articular Osteoid Osteoma as a Cause of Anteromedial Knee Pain

A 32-year-old male patient presented to our clinic with chronic left knee pain that was ongoing for about 1.5 years. The patient visited several times our clinic and the other clinics; conservative treatment (including rest, knee brace, and ice application with NSAIDs) was recommended by various different doctors. The anamnesis, physical examination, and plain radiography were nonspecific. Early MRI findings mislead us to believe it is bone marrow edema. One and half years with noneffective treatment, the knee pain persisted. At the latest visit intra-articular osteoid osteoma was suspected and the knee MRI with CT was employed. Even though the diagnosis of intra-articular osteoid osteoma often presents a challenge for the surgeons, with a present awareness of intra-articular osteoid osteomas which lack the characteristic sclerotic lesions and nidus on plain X-rays and the aid of multislice CT, a correct diagnosis which warrants proper treatment can be achieved. The possibility of osteoid osteomas, especially in young adults with persistent knee pain with unknown reasons that show normal plain radiographs results, must not be overlooked. The treatment method of these lesions should be customized depending on the location of the lesion, experience of the surgeon, and cost of method.