Osteoblastoma of the calvaria: report of two cases diagnosed with MRI and clinical review.

The authors describe 2 cases of osteoblastoma of the calvaria and review the clinical features of the 28 cases reported in the world literature. Benign osteoblastoma is a rare tumor that effects young patients, most frequently at temporal level. On the basis of its neuroradiological appearance, it is difficult to formulate a differential diagnosis against other osteoblastic tumors or against osteoid osteoma. In only a few cases MRI findings are reported. In our cases, MRI was more effective than CT scans and radiographs for evaluating the intracranial and intraosseous extension of the tumor. The definitive diagnosis was obtained by combining the histopathological features of the tumor with the clinical and radiological data. The prognosis of this tumor is very good regardless of the type of treatment performed, although both relapse and, more rarely, malignant tumor evolution are possible.