Leiomyosarcoma of the right renal vein with tumour thrombus extending to the right atrium – Case Report and literature review

Leiomyosarcoma (LMS) is a mesenchymal neoplasm accounting for 20% of all soft tissue sarcomas (STS), with a particularly rare localization in the muscular layer of the venous vessels. The case report presents a patient with non-metastatic LMS of the right renal vein, spreading intraluminally, and reaching the right atrium of the heart, supplemented with a review of the state of knowledge. The patient underwent radical treatment, including radical nephrectomy with <i>en bloc</i> thrombectomy under extracorporeal circulation without circulatory arrest and deep hypothermia. Histopathological examination diagnosed LMS and negative surgical margins. A computed tomography (CT) scan performed on the 45th postoperative day detected no early recurrence or metastatic features. The world literature describes 78 cases of renal vein (RV) LMS. Surgical treatment has the greatest overall survival (OS) impact. Adjuvant systemic treatment and radiotherapy do not improve OS outcomes, having only palliative significance.