ABSTRACT

Primary neoplasms that develop within the soft tissue parts of the retroperitoneum are relatively rare, but they are generally malignant and may progress to a significant size at the time of diagnosis. Although imaging findings are not specific, some characteristic features may play an important role in radiological detection, diagnosis, staging and preoperative evaluation of the tumor. The origin, location and size (e.g., presacral or paravertebral regions), tissue composition (fat content, fibrous tissue, cystic structures, etc.), signal characteristics on magnetic resonance imaging, vascularity, relationship with adjacent structures and extent of invasion of the tumor can all be evaluated radiologically. Identifying the macroscopic and microscopic histological features of the tumor may also facilitate correct diagnosis. Primary solid retroperitoneal tumors can be classified according to their origin and the soft tissue elements they contain, by imaging findings. Furthermore, imaging findings can be utilized to distinguish benign from malignant tumors and decide the best treatment strategy.