Pelvic tumors in childhood

Pelvic neoplasms can arise from the genitourinary tract, gonads, or soft tissues. When a pelvic mass is detected on physical examination or a conventional radiographic study, imaging evaluation is performed to characterize the lesion further and determine its site of origin and extent. Ultrasonography is used initially for the evaluation of most suspected lower genitourinary and testicular masses, because it does not use ionizing radiation. If the lesion is malignant, CT scan or MR imaging are warranted to detect the extent of pelvic invasion prior to surgery, chemotherapy, or radiation therapy. CT scan and MR imaging can also be helpful when sonography is suboptimal because of abundant bowel gas, a problem often encountered in evaluating the presacral space. CT scan and MR imaging are not degraded by bowel gas, and hence are most useful for evaluating a presacral mass. When a presacral mass is suspected to be malignant, MR imaging is superior to CT scan to detect intraspinal invasion and soft tissue infiltration.