Ultrasonography and computed tomography for diagnosis and follow-up of pelvic rhabdomyosarcomas in children.

The authors report 18 cases of pelvic rhabdomyosarcomas in children examined at presentation and followed on US and CT. There were 11 boys, 7 girls; tumor location was bladder, prostate or uterus in 12, perineum in 4, buttock in 2. US is good to define tumoral extension within the bladder CT is better to delineate the extension outside the bladder and regional spread to iliac nodes. CT is the only useful examination for perineal tumors. During chemotherapy US can be frequently repeated to appreciate tumoral regression and to give measurement of the mass. Preoperative CT should be performed when tumoral regression seems sufficient to permit complete tumoral excision without pelvic exenteration. Correlation between US and CT and surgical findings proved to be good. US and CT are also very useful in the follow-up when the child has finished treatment as it can demonstrate a local recurrence before clinical symptoms appear. However, post-surgical and post-radiation changes may be difficult to recognize. These aspects are discussed.