Retroperitoneum

Abstract

Soft tissue sarcomas are rare tumors, with less than 8,500 cases predicted in the United States in 2008. Tumors of the retroperitoneum are even more unusual because they comprise 10–20% of all sarcomas in adults. Of the malignancies that arise in the retroperitoneal space, and not in the retroperitoneal viscera, soft tissue sarcomas account for 40–70%. Lymphomas account for 15–30% of the total, and the less common tumors such as paragangliomas and malignant teratomas account for the remainder. The most frequent histologic types of retroperitoneal sarcoma are lipos-arcoma and leiomyosarcoma, followed by malignant fibrous histiocytoma and fibro-sarcoma. Less common histologic types include malignant peripheral nerve tumors, lymphangiosarcoma, rhabdomyosarcoma, and hemangioendothelioma.

Soft tissue sarcomas arising in the retroperitoneal space present a challenge to surgeons because they tend to grow silently to a large size before detection, may invade adjacent organs, and as a result, may limit the surgeon's ability to resect them with adequate negative margins. Despite the difficulties of surgical resection, aggressive complete or near complete resection is the mainstay of treatment. Survival is related to the extent of resection. Unresected disease is uniformly fatal. Complete resection of retroperitoneal sarcomas leads to a 5-year survival rate of more than 50%, and for some low-grade tumors, even partial resection (defined as resection of more than 80–90% of the tumor) has led to a 5-year survival rate of more than 40%. Patients with recurrent local disease are candidates for aggressive repeat resection, as complete resection may lead to a median survival of 41 months. Unfortunately, repeated recurrences have decreasing benefit from surgical resection with patients successfully undergoing surgery for a second resection only 20% of the time and for a third recurrence less than 10% of the time. Patients with isolated lung metastases may also undergo metastasectomy with a measurable survival benefit.