a 76-year - old male ex - smoker presented with a recent history of hematuria and transient right - flank pain . on physical examination , no mass was palpable in the abdomen , and no costovertebral angle tenderness was found . hemogram and blood chemistry results were normal , except for azotemia ( serum creatinine , 2.2 ng / ml ) . magnetic resonance urography confirmed an irregular ureter mass 2 cm from the ureterovesical junction of approximately 5 cm ( fig . cystoscopy showed no abnormalities in the urinary bladder , and the findings of urine cytologic examination were negative . grossly , several small and large simple cysts were observed in the renal cortex , of which the largest measured 32 cm . the distal end area was dilated , and an irregular polypoid mass measuring 51.51.2 cm was identified 2 cm from the bladder cuff ( fig . 2 ) . microscopically , a population of mononuclear cells with numerous interspersed multinucleated giant cells were observed . the mononuclear cells contained round- to oval - shaped nuclei with vesicular chromatin , inconspicuous nucleoli , moderate nuclear clearing , and mild nuclear pleomorphism . ogcs had multiple round - to - oval , bland - appearing nuclei ranging from 4 to 34 in number . the tumor invaded focally into the periureteric adipose tissue and was categorized as american joint committee on cancer stage pt3nxmx . immunohistologic examination showed that the multinucleated giant cells were positive for cd68 , cd45 , epithelial membrane antigen ( ema ) , vimentin , and cytokeratin ( cytoplasmic but not nuclear staining ) and negative for desmin and cd31 ( fig . the 5-month postsurgical follow - up , the patient was doing well , had no evidence of disease recurrence , and had a serum creatinine level of 2.5 ng / ml . extraskeletal ogc carcinoma of the urinary tract is extremely rare and has most frequently been reported in the breast and pancreas . fewer than 30 case reports of ogc tumors of the urinary tract have been published in the english literature [ 2 - 6 ] . the most common tumor locations in the urinary tract are the kidney , renal pelvis , and bladder . only one case of ogc carcinoma of the bladder with right ureter invasion has been reported . to the best of our knowledge , this is the first case report of an ogc carcinoma of the distal ureter without a bladder tumor . much controversy exists regarding the nature and origin of epithelial , histiocytic , and mesenchymal ogcs . one study indicated that these types of ogcs may result from the fusion of mononuclear histiocytes / macrophages , which are attracted to the tumor by growth or chemotactic factors released by neoplastic epithelial cells . immunohistochemical analysis in this previous study showed that the ogcs were positive for vimentin , ema , and the cell surface proteins cd68 and cd45 and were negative for cytokeratin . as is well known , hematuria and flank pain are the most common and frequent initial symptoms . the appearance of ogc carcinoma under cystoureteroscopy is similar to that of other urothelial tumors . because of the rarity of ogc tumors in the urinary tract , previous reports indicate that the median survival rate associated with ogc tumors is less than 2 years . aggressive management is recommended because of the poor prognosis of this condition ; however , no adjuvant treatment has yet been established . adjuvant radiation therapy may be beneficial , because giant cell tumors of the bone are radiosensitive . although adjuvant chemotherapy , such as mitoxantrone / etoposide / cyclosporine , has been reported to be beneficial in patients with transitional cell carcinoma of the urinary tract , a large population - based study is needed to confirm the benefits of such therapy in the treatment of invasive ogc tumors of the urinary tract . previous reports indicate that extensive surgical excision appears to be the recommended treatment for primary or recurrent lesions until the treatment benefits of adjuvant chemotherapy or radiotherapy are established .