Vertebral Fractures of Unknown Origin: Role of Computed Tomography-Guided Biopsy

Background We performed a retrospective evaluation of histological and imaging results of patients submitted to computed tomography (CT)-guided biopsy for vertebral fractures (VFs) of unknown etiology to evaluate the pathological causes of fractures and also to observe the diagnostic results of imaging studies available.

Methods We retrospectively reviewed all the CT-guided vertebral biopsies performed in our institution in the last 2 years, selecting patients with VF of unknown etiology. We reviewed clinical records, imaging studies, and histological examination results. We compared diagnostic performance of the 2 most sensitive imaging modalities for detection of malignancy on the collapsed vertebral body: magnetic resonance imaging (MRI) and positron emission tomography-CT (PET-CT). Anatomopathological results have been considered the gold standard to assess the diagnostic performance of imaging studies. Age stratification has been performed to understand the distribution of different anatomopathological diagnoses in age groups.

Results Among 282 CT-guided vertebral biopsies, 36 (12.8%) have been performed to diagnose the etiology of VF of unknown origin. In 26/32 (81.3%), the vertebral biopsy was diagnostic: 8 osteopenia, 6 multiple myelomas, 4 osteomyelitis, 2 eosinophilic granuloma, 3 metastases, 1 mastocytosis, 1 Paget's disease, and 1 dysmielopoiesis. In 6 cases, the anatomopathological diagnosis was normal bone structure, most likely excluding malignancy. There were no statistically significance differences between MRI and PET-CT results (P = 1.0000).

Conclusions Multiple myeloma and osteopenia represent the most frequent causes of this condition in adult patients, while eosinophilic granuloma and osteomyelitis in pediatric patients. Computed tomography-guided biopsy permits one to reach diagnosis in most of cases. Both PET and MRI could be insufficient to discriminate benign from malignant causes of fractures. Computed tomography-guided biopsy is needed when the etiology of fracture remains unclear.