Osteoid osteoma: topographical distribution and imaging features in children and adults

To investigate how the topographical distribution and CT/MRI/scintigraphy characteristics of osteoid osteoma (OO) differ between children and adults.

Patients who underwent percutaneous thermal ablation of OO between May 2008 and April 2025 in a single center were retrospectively evaluated. A skeletal atlas of the distribution of OO was created for children and adults. Patient gender, topographical data (skeletal region, intraarticular status, classification relative to the cortex) and imaging features (size, surrounding sclerosis or periosteal reaction, central calcifications, presence of the vessel sign, bone marrow edema, MRI contrast uptake and bone tracer uptake) were compared between children and adults.

315 patients (median age, 21 years, IQR, 15-31; 203 men), including 104 children and 211 adults, were evaluated. There was a higher proportion of female patients in the pediatric group (43% vs. 32%, p = 0.045). Adults had a higher rate of intraarticular OO (67% vs 46%, p < 0.001), more spinal lesions (29% vs. 13%) and fewer lower extremity lesions (57% vs. 76%, p = 0.005). OO in adults were smaller (7.35 ± 2.64 mm vs. 8.44 ± 2.74 mm, p < 0.001) and were less frequently associated with perifocal sclerosis or periosteal reaction (67% vs. 86%, p < 0.001), bone marrow edema (88% vs. 100%, p = 0.04) and the vessel sign (39% vs. 66%, p < 0.001).

Osteoid osteoma in adults demonstrate less typical imaging features and occur in less typical locations compared to children. Awareness of these age-related differences is important when evaluating musculoskeletal pain and especially joint-related symptoms.