A 39-year-old female visited our hospital because of a bladder tumor. Computed tomography and magnetic resonance imaging showed a retrovesical tumor in dome of the bladder. Cystoscopy showed edematous inflammatory changes of the mucosa of the bladder wall. We diagnosed her with urachal carcinoma from cystoscopy finding and image inspections. She received partial cystectomy with pelvic lymphadenectomy. Histopathological examination revealed inflammatory myofibroblastic tumor because these specimens presented positive for anaplastic lymphoma kinase in immunohistochemical studies. She has been followed up for 16 months without any evidence of local recurrence.