Emergency Surgery in High Volume Osteosarcoma of Left Proximal Humerus Due to Vascular Compromise: A Case Report.

BACKGROUND Osteosarcoma is the most common type of malignant bone tumor arising from mesenchymal stem cell. When occurring on the proximal humerus, it is associated with poor outcomes; there are numerous neurovascular structures around proximal humerus. Unfortunately, the degree of vascular involvement in osteosarcoma is rarely evaluated and reported.