Imaging of primary malignant tumors of peritoneal and retroperitoneal origin.

Peritoneal carcinomatosis and metastatic involvement of the retroperitoneum are relatively common manifestations of many organ-based malignancies and lymphoproliferative disorders. Primary malignancies of peritoneal and retroperitoneal origin occur much less frequently, and can be difficult to distinguish from metastatic disease. In many cases, a precise diagnosis based on imaging findings alone is not possible. However, the imaging features of these primary tumors, in combination with the clinical and demographic data, can be utilized to narrow the scope of the differential diagnosis. This chapter will present the clinical and imaging features of primary peritoneal and retroperitoneal tumors arising from the various tissue components that comprise the ligaments, mesenteries and connective tissues of these anatomic spaces.