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Updated: Jan 2, 2026

Modeling Primary Bone Tumors and Bone Metastasis with Solid Tumor Graft Implantation into Bone
Published on: September 9, 2020
Can Osteoblastoma Evolve to Malignancy? A Challenge in the Decision-Making Process of a Benign Spine Tumor
Addisu Mesfin1, Stefano Boriani2, Marco Gambarotti3
1Department of Orthopaedic Surgery, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; Department of Neurosurgery, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
Background:
Osteoblastoma is a rare benign aggressive tumor, with one third occurring in the spine. Conversion of osteoblastoma to osteosarcoma is uncommon, and histologically proven conversion has been rarely reported.
Case Description:
Cases of 2 patients with rare occurrences of spinal osteoblastomas recurring and transforming into osteosarcomas are presented. Initial presentation, treatment, imaging, and histology findings are described. The outcomes of the patients following surgical intervention for histologically diagnosed osteoblastoma with subsequent transformation to osteosarcoma and relative management are described. A literature review of osteoblastoma converting to osteosarcoma also is provided.
Conclusions:
The rare occurrence of osteoblastoma converting to osteosarcoma imparts several lessons, including performing Enneking appropriate surgery for benign aggressive tumors (Enneking stage 3) and always performing a biopsy, particularly at the time of recurrence if imaging is not pathognomonic for a benign primary spine tumor.
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