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Renal involvement in primary retroperitoneal tumors

Retroperitoneal tumors grow quietly and are generally large in size, more than half of them being larger than 20 cm at the time of diagnosis. They usually present several therapeutic challenges because of their rarity, relative late presentation and anatomical location, often in close relationship with several important structures in the retroperitoneal space. Due to intimate relationships with vital organs in retroperitoneum, extensive surgery with en bloc resection of the involved organ is often required, most frequently the kidneys, followed by colon, pancreas and spleen. Malignant tumors have a poor prognosis, the most significant factors regarding survival rates being delayed diagnosis, high histological grade, inoperability due to invasion into vital organs, and a positive surgical border.