Retroperitoneal sarcomas are a varied group of malignancies which have a high rate of recurrence following surgery alone. The majority of the initial recurrences are local in nature, and new therapeutic approaches are clearly needed. Diagnostic imaging and "interventional radiology" have important roles to play in the management of these malignancies, as well as in investigational approaches to therapy. Two cases are presented which illustrate some recent advances in diagnosis and staging of this group of tumors which can be attributed to new cross-sectional imaging techniques, when used in concert with "conventional" imaging methods. The latter include arteriography to guide the placement of intra-arterial catheters for local infusion chemotherapy. CT-guided needle biopsies can be performed to secure a preoperative diagnosis and also to obtain viable tissue for in vitro chemosensitivity assays. A judicious combination of local and systemic chemotherapy, radiation, and surgery may hold promise for better control of this malignancy, similar to the therapeutic advances which have already been obtained with limb sarcomas.

A case is presented of an embryonal sarcoma of the liver in a young child. The differential diagnosis of liver masses in children is reviewed, as well as the implications of diagnostic imaging studies for diagnosis, prognosis, staging, and the choice of treatment. The use of diagnostic imaging for guiding interventional diagnostic procedures and certain palliative approaches is also discussed.