Seventeen (13 male, 4 female) patients, aged 13 months to 13 years, with benign cystitis had imaging findings that mimicked those of rhabdomyosarcoma. Our experience indicates that in the child with hematuria, dysuria, and frequency plus cystographic or sonographic demonstration of a bladder with reduced capacity and circumferential wall thickening or sonographic findings of isoechoic bladder wall thickening (focal, multifocal or circumferential distribution), intact mucosa, and bullous lesions should strongly suggest inflammation and not malignancy. When an inflammatory lesion is suspected, follow-up imaging should be performed in 2 weeks, which if normal will preclude biopsy.