[Uncommon tumor-associated deep vein thrombosis].

Here, we report on a patient with deep vein thrombosis of the right leg, in whom diagnostic work-up revealed a previously unknown chondrosarcoma of the tibia. Physical examination revealed a firm, nondisplaceable mass on the dorsal side of the right knee that appeared as a cystic formation on ultrasound. X‑ray, computed tomography, and magnetic resonance imaging were consistent with chondrosarcoma, which had likely provoked the thrombosis by local compression or paraneoplastic mechanisms. After resection of the tumor, anticoagulation was continued. In a review of all findings, a final diagnosis of highly differentiated chondrosarcoma with thrombosis of the popliteal vein was made.