Aggressive Cranial Osteoblastoma of the Parietotemporo-Occipital Bone: A Case Report and Review of Literature with Special Emphasis on Recurrence/Residue.

Abstract

Osteoblastoma is a rare nonfibroblastic osteoid tissue-forming primary bony tumor usually arising in the medullary cavity/diploic space of any bone. The calvarium is an extremely rare site of its origin. Clinically, 2 types of osteoblastoma are noted: benign/conventional/typical and aggressive/high grade. Their imaging features are nondifferentiating and nonspecific, histopathologic features have a few subtle but nonspecific differences, and they have highly distinct clinical behavior. We report an extremely rare case of a patient with large aggressive cranial osteoblastoma, who developed massive inoperable multifocal recurrence 15 months after total en bloc resection with wide margins. A concise review of cases of aggressive osteoblastomas involving the cranium available in the English literature is also presented as an update.