DRAGOS RADU MARCU, FLORENTINA IONITA-RADU, LUCIAN DANIEL IORGA, MARIA MANEA, BOGDAN SOCEA, IOAN SCARNECIU, GHEORGHITA ISVORANU, RALUCA COSTACHE, CAMELIA CRISTINA DIACONU, OVIDIU GABRIEL BRATU VASCULAR INVOLVEMENT IN PRIMARY RETROPERITONEAL TUMORS The retroperitoneum can host a wide variety of pathologies, including benign and malignant tumors. Primary retroperitoneal tumors are rare, usually large in size, more than half of them being larger than 20 cm at the time of diagnosis, due to their silent growth. They often present several therapeutic challenges because of their rarity, relatively late presentation and anatomical location, often in close relationship with several important structures in the retroperitoneal space. Extensive surgery is often required because of the intimate relationships with vital organs in the retroperitoneum. Retroperitoneal sarcomas frequently involve major vessels, originating from them or secondarily encase or invade them, requiring major vascular resections, with increasing morbidity. The main intervention that can increase the survival of patients with retroperitoneal tumors is radical resection. The involvement of large retroperitoneal vessels often makes impossible a radical intervention, usually because of the lack of an adequate material for ample and laborious vascular reconstruction. In this paper, a thorough search of the PubMed database was performed, to bring into the light the implications of vascular involvement in primary retroperitoneal tumors and the need of a strong cooperation between the urological or general surgeon and the vascular surgeon.