Typical and atypical radiographic features of symptomatic osteoblastoma in the spine.

PURPOSE: Spine osteoblastomas (OBs) are relatively rare. Unlike osteoid osteoma (OO), radiological and clinical manifestations of OB can be varied and atypical. Typical radiographic features in spinal OB include peritumoral bone sclerosis, bone marrow edema, and soft tissue edema. Atypical radiographic features include lesions involving three or more segments, lesions with extensive (≥3 segments) bone sclerosis, excessive edema (≥3 segments) of soft tissue and bone marrow, no intralesional calcification, and lesions located in the vertebral body only. The purpose of this study was to identify the typical and atypical features of OB.

METHODS: In this retrospective study, pretreatment computed tomography (CT) scans and magnetic resonance imaging were reviewed retrospectively. Percutaneous biopsies were performed to confirm pathology in atypical cases.

RESULTS: A total of 50 images from patients with diagnosed OB were reviewed. Typical radiographic features in spinal OB include peritumoral bone sclerosis, bone marrow edema, and soft tissue edema. Atypical radiographic features include lesions involving three or more segments, lesions with extensive (≥3 segments) bone sclerosis, excessive edema (≥3 segments) of soft tissue and bone marrow, no intralesional calcification, and lesions located in the vertebral body only. Atypical radiographic features were found in 18 cases (36%). Pathological diagnosis was confirmed as OB in 86.2% (25/29) cases after percutaneous CT-guided biopsy.

CONCLUSIONS: Our results show that more than 30% of spinal OB cases might have atypical radiographic features. In cases with atypical radiographic features, CT-guided biopsies are recommended.