Eosinophilic Granuloma Arising from the Sacrum: A Case Report

Introduction: Osseous eosinophilic granulomas commonly occur in the skull, pelvis, vertebrae, mandible, and ribs. However, the eosinophilic granuloma in the sacrum is rare. Case presentation: We present the case of a 13-year-old Japanese boy, who presented with left low-back pain, and was diagnosed with eosinophilic granuloma arising in the sacrum. Computed tomography (CT) and magnetic resonance imaging demonstrated an osteolytic lesion with interruption of the cortex, and signal intensity changes at the left sacral body and wing. Histologic examination indicated an eosinophilic granuloma. Two years after CT-guided biopsy, the tumor had spontaneously healed completely, with no residual pain. Conclusion: The present case was eosiophilic granuloma arising from the rare site of sacrum. The tumor was completely remodeled two years after biopsy.