Management Strategies and Outcomes of Tumor Thrombus in Extremity Osteosarcoma.

Osteosarcoma, accounting for 2.4% of all childhood malignancies and about 20% of primary bone cancers, primarily affects young adults, with 60% of cases occurring before age 25. Tumor thrombus (TT) formation, a type of cancer-associated thrombosis, is a rare but critical complication in osteosarcoma, leading to increased morbidity and mortality. TT is characterized by the direct extension of the tumor into adjacent vessels, displaying similar imaging characteristics and contrast enhancement as the primary tumor. Our study is a case series of five cases of extremity osteosarcoma where the presence of tumor thrombus has been diagnosed, highlighting diagnostic challenges and management strategies. Preoperative identification of TT remains difficult and is often diagnosed postoperatively or at autopsy. Advanced imaging techniques such as Computed Tomography, Magnetic Resonance Imaging, and Positron Emission Tomography can aid in the detection of TT, although they are not definitive. Surgical resection combined with thrombectomy is recommended, improving prognosis. Anticoagulation therapy aims to prevent bland thrombus formation rather than resolving TT, as the latter increases the risk of embolization. This study underscores the need for heightened suspicion and comprehensive preoperative imaging to improve outcomes in osteosarcoma patients with TT, advocating for multidisciplinary management including vascular surgeons during limb salvage procedures. Further research is essential to optimize anticoagulation protocols and validate these findings in larger cohorts.