Atypical Radiographic Features of Aggressive Vertebral Hemangiomas

Background: Vertebral hemangioma (VH) is one of the most common benign spinal tumors and can be aggressive in some cases. While most aggressive VHs have typical radiographic features, including vertical striations, a honeycomb appearance, and/or a "polka-dot sign" in computed tomography (CT) scans, cases with atypical features might complicate diagnosis. This study aimed to determine the range and frequency of these features. Methods: In this retrospective study, to identify the typical and atypical features of aggressive VH, pretreatment CT and magnetic resonance imaging (MRI) were reviewed retrospectively by 1 radiologist and 1 orthopaedic surgeon. Percutaneous biopsies were performed to confirm the VH in atypical cases. Results: A total of 95 patients with aggressive VHs were treated in our hospital from January 2005 to December 2017. Thirty-four (36%) of the lesions showed at least 1 atypical radiographic feature: 16 patients (17%) had a vertebral compression fracture, 11 patients (12%) had expansive and/or osteolytic bone destruction without a honeycomb appearance and/or "polka-dot sign", 11 patients (12%) had obvious epidural osseous compression of the spinal cord, 12 patients (13%) had involvement of >1 segment, 9 patients (10%) had a VH centered in the pedicle and/or lamina, and 8 patients (8%) had atypical MRI signals. Forty-three patients underwent percutaneous biopsies, which had an accuracy of 86%. Conclusions: Based on radiographic analysis, aggressive VH can be classified as typical or atypical. More than one-third of aggressive VH lesions may have at least 1 atypical feature. CT-guided biopsies are indicated for these atypical cases.