a 50-year - old female presented to the emergency department with complaints of weakness , right lumbar pain , and painless total hematuria . she had lost 20 kg of weight in the past 2 months and her hematuria had been present for the past month with no history of trauma . the physical examination was unremarkable except for increased sensitivity on her right flank and hemoglobin and hematocrit values of 6.9 mg / dl and 20% , respectively . owing to clot retention , continuous bladder irrigation was initiated and her hemoglobin levels were corrected with transfusions . computed tomography ( ct ) scans of the chest , abdomen , and pelvis showed a 9 cm cystic renal mass on the right and another 5 cm tumor on the left kidney ; a subpleural 5 cm lesion was visible on the right lower lobe of the lung ct ( fig . 1 , 2 ) . an ultrasound - guided tru - cut biopsy of the right kidney was performed with a pathologic diagnosis of xanthogranulomatous pyelonephritis . fine - needle aspiration biopsy of the lung lesion was reported as the coagulation type of necrosis . after cystoscopic evaluation to disclose the source of the hematuria , right transperitoneal radical nephrectomy was performed . the surgery was uncomplicated except for a 3 cm tear in the vena cava that was primarily sutured . on the first postoperative day an increase in serum bilirubin levels was detected and the patient developed tachypnea and dyspnea . a repeat ct scan of the chest and abdomen demonstrated multiple lesions in the liver and spleen that were not visible on the preoperative scans , with an increase in size and number of the lesions in the lung . the patient 's recovery period was troublesome and extended ; nevertheless , no further surgical intervention was necessary . 3 ) ; assessment of the serum beta - human chorionic gonadotropin level was over 1 million miu / ml . the final diagnosis was gestational choriocarcinoma , and the patient was referred to the oncology department for methotrexate - based chemotherapy following stabilization of her general status . gestational choriocarcinomas are mostly seen in women of reproductive age , generally within 1 year after a molar or nonmolar pregnancy . the risk of developing choriocarcinoma is exceptional before 20 years of age but increases significantly from 40 years onward . lung , vagina , and brain metastasis occurs in 50% , 30% , and 10% of cases , respectively ; liver and kidney metastasis is less common . urological involvement with gestational trophoblastic neoplasia is relatively rare , but renal involvement may cause massive retroperitoneal hemorrhage . renal metastases can cause abdominal pain , hematuria , or oliguria but are more usually found as incidental mass lesions during radiological staging . according to the international society for the study of trophoblastic disease , the incidence of renal metastases from choriocarcinoma is rare and can result in perinephric hemorrhage and lead to spontaneous rupture . the case we reported here presented with gross hematuria originating from the right kidney that was confirmed by cystoscopic evaluation . additionally , no evidence of other metastasis was determined except for the lesion in the lung , which could not be diagnosed by fine - needle biopsy . wang et al reported that renal metastases were invariably preceded by lung metastasis ( 100% ) , indicating that renal metastasis is most likely the result of dissemination of tumor cells through the general circulation secondary to lung metastasis . however , this seems not to have been the case in our patient , in whom dissemination of lung metastases occurred after radical nephrectomy . choriocarcinoma is preceded by a hydatidiform mole 60% of cases , by previous miscarriages in 23% , by full - term pregnancy in 10% , and is primary in 5% of cases . our case had a choriocarcinoma with a history of a hydatidiform mole 5 years previously . the international federation of gynecology and obstetrics ( figo ) staging for trophoblastic diseases that was devised in 1992 was improved in 2002 by combining the basic anatomic staging with the modified who risk factor scoring system . the diagnosis and treatment of choriocarcinoma is based on the biological behavior of the tumor rather than a histopathological diagnosis . use of the figo staging system is essential in determining initial therapy for patients with gestational trophoblastic neoplasia to ensure the best possible outcomes with the least morbidity . our case was staged as iv : 20 according to the figo 2002 scoring system . patients with high - risk metastatic gestational trophoblastic neoplasia ( figo stage iv and stages ii - iii score 7 ) should be treated initially with multiagent chemotherapy with or without adjuvant surgery or radiation therapy . multiagent chemotherapy , a combination of etoposide , high - dose methotrexate with folinic acid , actinomycin d , cyclophosphamide , and vincristine ( ema - co ) , results in improved remission and survival rates . virtually 50% of high - risk patients require surgical treatment during the course of treatment . in conclusion , this case demonstrates that metastatic choriocarcinoma can present with flank pain , hematuria , and a renal mass imitating renal cell carcinoma . also interesting in our case was the occurrence of bilateral renal masses followed by disseminated multi - organ metastases at 5 years after a hydatidiform mole treated with total abdominal hysterectomy and bilateral salpingo - oophorectomy . the patient was referred to medical oncology after the right radical nephrectomy and is still undergoing a chemotherapy protocol .
choriocarcinoma is the most malignant tumor of gestational trophoblastic neoplasia . 
 it grows rapidly and metastasizes to the lung , liver , and less frequently , the brain . 
 metastases to the kidney are rare in the literature , and bilateral involvement is even more scarce . 
 renal involvement of choriocarcinoma is highly exceptional and may mimic renal cell carcinoma . 
 here we report a case of bilateral renal choriocarcinoma presenting 5 years after a history of a total anterior hysterectomy because of a hydatidiform mole .