Leiomyosarcoma (LMS) of the inferior vena cava (IVC) is a rare malignant tumor, accounting for 2% of all LMSs. Less than 400 cases have been reported in literature. Computed tomography (CT) is the most accurate imaging method in assessing the location of the tumor within the IVC and magnetic resonance imaging (MRI) accurately identifies its extent and the potential for surgical resection. We present the case of a patient with inferior vena cava leiomyosarcoma (IVCL), for whom the pathological diagnosis was different from the initially expected one, the tumor appearance on pre-operative imaging mimicking renal cell carcinoma. The intraoperative difficulty of approaching renal hilum and IVC was a factor suggesting the vascular origin of the tumor, which was confirmed at pathological analysis. The extensive defect in the IVC after tumor excision led to the decision of complete transverse suturing of IVC, as significant collateral venous circulation was already present. Because IVCL is a rare disease, there is scarce data regarding the prognosis and treatment options. Long-term survival depends on the extent of the surgery. The need of vascular reconstruction is not always mandatory. Despite high recurrence rates, no consensus regarding adjuvant treatment exists yet. A multidisciplinary approach including surgical oncologists and vascular surgeons is mandatory to achieve the best patient outcomes. Perioperative planning, coordination and adherence to oncological techniques are critical.