Radiographic evaluation can be helpful in further defining the tumor Ultrasound can define the anatomic position of the mass, explore whether it has cystic or solid components, and assess for any hydronephrosis or ureteral obstruction The radiologist should assess for tumor thrombus in renal veins or inferior vena cava Centers skilled in pediatric imaging may elect to perform a CT scan with intravenous contrast If it is certain that the mass is renal in origin, it is appropriate to include the chest to evaluate for the presence of lung metastasis Management The initial management of renal masses should focus on a determination of how ill the patient is and consultation with a pediatric oncologist or pediatric surgeon Wellappearing patients without evidence of bleeding may be discharged if appropriate follow-up with a pediatric oncologist or surgeon is arranged TUMORS OF THE LOWER GENITOURINARY TRACT While tumors of the lower GU tract in adults are most commonly carcinomas, in children these tumors are more likely to be sarcomas Their presentation is determined by their location Vaginal tumors are most commonly rhabdomyosarcomas of the botryoid histology These tumors classically present protruding from the vagina, accompanied by a mucous/bloody discharge Uterine tumors more commonly present in adolescent girls and may cause a palpable mass or vaginal discharge Tumors of the bladder may present with hematuria, urinary obstruction, or extrusion of tumor tissue from the urethra Bladder tumors, most common in children younger than years, are usually within the lumen of the bladder Prostate tumors are usually rhabdomyosarcomas that can cause constipation, urinary obstruction, or a large pelvic mass Paratesticular tumors present as painless unilateral scrotal enlargement or swelling (see section on “Gonadal Tumors” for details on testicular tumors) The management of patients presenting with these tumors should begin with a thorough history and physical examination Children are not usually acutely ill at the time of presentation Most of the evaluation can be done on an outpatient basis, in consultation with a pediatric oncologist The emergency clinician should ensure adequate bowel, bladder, and renal function as well as appropriate analgesia An ultrasound may be useful to determine where the tumor is located The most common reason for admission is management of urinary obstruction GONADAL TUMORS In children, most gonadal tumors are derived from malignant transformation of the primordial germ cells, although other tissues within the gonads may be the source of malignant cells Presentation of these tumors varies based on the gender of the