Malignant transformation of an osteoblastoma of the mandible: case report and review of the literature.

Benign osteoblastoma is a rarely seen tumor of the facial bones. The authors present a case of a 30-year-old man with a tumor of the mandibular body and ramus. The histopathological diagnosis was one of osteoblastoma. Postoperative recurrence with soft tissue infiltration suggested an osteosarcoma radiologically, but the histological examination again revealed the presence of an osteoblastoma. A second recurrence occured in the pharyngo-glossal region and this time the tumor was histologically diagnosed as an osteoblastoma, but with foci of well-differentiated osteosarcoma. The patient was given a course of radiotherapy, but clinical and radiological examination 8 months later revealed lung metastases and chemotherapy was started. Unfortunately, the patient died months later. While osteoblastomas are rare, and their sarcomatous change even rarer, our experience with this case lead us to suggest that a therapeutic preventative approach, involving both chemotherapy and total excision of the tumor, is the regime to adopt with osteoblastomas which involve soft tissues and have radiological features suggesting malignancy.