The tumor embolus from osteosarcoma showed a Ki-67 proliferation index of 10% to 20%.
Pearls & Oy-sters: Acute Cerebral Occlusion due to Parosteal Osteosarcoma Embolus.
Jian Wang … Fa-Yun Hu
Neurology · Aug 2026
Background
Tumor embolism is a rare cause of acute ischemic stroke.
Results
10%-20%
this percentage of the tumor's cells were actively dividing, showing its rate of growth
More results
We present a case of a 46-year-old man with a history of distal femoral amputation 11 years prior due to parosteal osteosarcoma who developed acute onset left-sided weakness.
Computed tomography (computed tomography) angiography revealed occlusion of the right middle cerebral artery (middle cerebral artery).
More results
Fluorescence in situ hybridization (FISH) confirmed amplification of the MDM2 gene, supporting the diagnosis of metastatic dedifferentiated parosteal osteosarcoma.
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Conclusion
Mechanical thrombectomy was pivotal not only for restoring cerebral perfusion but also for obtaining tissue for definitive histopathologic diagnosis.