Primary Renal Fibrosarcoma with Massive Tumor Size and Inferior Vena Cava Extension Mimicking Renal Cell Carcinoma: A Rare Case Report. jkcvhl [Internet]. 2026 Jan. 12 [cited 2026 Apr. 17];13(1):6-11. Available from: https://mail.jkcvhl.com/index.php/jkcvhl/article/view/430