 Histologically, osteoblastomas are similar to osteoid osteomas, producing both osteoid and primitive woven bone amidst fibrovascular connective tissue, the difference being that osteoblastoma can grow larger than 2.0 cm in diameter while osteoid osteomas cannot.Although the tumor is usually considered benign, a controversial aggressive variant has been described in the literature, with histologic features similar to those of malignant tumors such as an osteosarcoma.When diagnosing osteoblastoma, the preliminary radiologic workup should consist of radiography of the site of the patient's pain.