Aggressive osteoblastoma. A case report and review of the literature.

A recurrent osteoblastoma involving the acetabulum in a 27-year-old woman was found to be locally aggressive and histologically appeared to become more anaplastic with each recurrence. However, there was no evidence of distant metastases. Similar cases have been reported under such names as pseudomalignant or malignant osteoblastoma. In view of the prolonged clinical course without evidence of distal metastases, the term "aggressive osteoblastoma" seems to be more appropriate. The treatment of choice for such tumors should be further en bloc resection, avoiding the morbidity and possible mortality of the chemotherapy demanded by true malignant tumor of bone, as well as unnecessary ablative surgery.