wilms ' tumor is the second most common solid neoplasm and the most common malignant renal tumor in childhood affecting 1/1,000 of children12 ) . survival correlates with tumor histology , as children , with favorable tumor histology have good survival rates despite widespread disease ( 5-year survival rate is over 80%)3 ) . lung is the most common metastatic site thereafter liver , lymph nodes and bone2 ) . we present a rare case of wilms ' tumor with multiple brain metastases harboring anaplastic features . an 8-year - old girl , with a previous diagnosis of wilms ' tumor , admitted to our emergency department with new onset generalized tonic - clonic seizure . after we stabilized her status , emergency computed tomography scan showed posterior fossa intraparenchymal mass . contrast enhanced brain magnetic resonance imaging depicted homogenously enhanced multiple small metastases except a larger one in the right cerebellar parenchyma ( fig . she had had masses in both kidneys and had had distant metastases to lungs at the time of diagnosis ( stage v ) . she had been operated for bilateral kidney masses 3 months after her chemotherapy and had been put on chemotherapy once again after the surgery . she had been put on routine follow - ups since then . in her last clinic visit , distant metastases in the brain the tumor mass was sharply demarcated from the normal cerebellar tissue . the tumor had immature mesenchymal cells . in immunohistochemical staining , wt1 and gfap were positive ; ck was negative ( fig . , whole brain radiotherapy was given in another clinic , however her cranial masses progressed in time and she succumbed to her disease . the patient described in this case report , had been diagnosed of wilms ' tumor 5 years ago and had been treated accordingly . her brain metastases were diagnosed after a first - time tonic - clonic seizure attack . while recurrence of wilms ' tumor has been reported up to 25 years after primary diagnosis4 ) , brain metastases usually appear in 2 years . malogolowkin et al.5 ) made a meta - analysis of 10 consecutive trials conducted in wilms ' tumor patients . a total of 13,330 patients were enrolled into the analysis , which had a late recurrence rate of 0.5% . abdomen , lungs and contralateral kidney were found to be the most common sites of recurrences in these patients . three or more medications had been used in 32% and radiotherapy had been used in 37% of the patients with late recurrences5 ) . a huge difference in survival rates was present between the patients with recurrences in contralateral kidney and patients with distant organ recurrences ( 87% vs. 45% ) due to different cell lines they harbor . this means that recurrence in the contralateral kidney might not be a true metastasis , rather a de novo disease5 ) . abnormalities in wilms ' tumor suppressor genes wt-1 ( on 11p13 ) and wt-2 ( on 11p15 ) have been notified in the literature6 ) . immunohistochemical studies in the presented case were positive for wt-1 . beside these tumor suppressor genes , there are many defined molecular abnormalities on chromosomes 1p , 7p , 16q , 17p , and 19q78 ) . our patient had been treated in an outside clinic previously and we could not retrieve the past pathology slides to make a comparison between initial and late recurrent disease . in recent practice , solid tumor resection and adjuvant radiotherapy with chemotherapies are treatment of choices with good results . while some authors insist on aggressive therapy , some others recommend to treat these tumors same as recurrent disease in general59 ) . there is also no consensus over treatment modality for brain metastases of wilms ' tumor . however , median survival is 1 month for untreated patients , and sole treatment with only surgery or only radiotherapy is not enough for a long survival time210111213 ) . whole ( 30 gy in 10 fractions ) or local radiotherapy ( 3036 gy in 1.51.8 gy fractions ) to brain metastases are method of choices . a treatment regimen of vincristine , actinomycin d and cyclophosphamide were being used conveniently , however ifosfamide and etoposide have turned to be superior in terms of treatment success2 ) . the patient we presented had one solid mass in the cerebellum and multiple small metastases in the whole brain . we resected the solid tumor totally , and gave adjuvant radiotherapy to the whole brain , yet the patient died after the radiotherapy . one other point to consider in our patient was bilateral kidney masses at the initial presentation . after initial chemotherapy , the patient had had a nephron sparing surgery in both kidneys . bilateral nephron sparing surgery is a challenging situation against aggressive chemotherapy regimen in respect of toxicity14 ) . prognostic factors for patients with relapse are site of relapse , length of initial remission , initial treatment regimen ( 2 or 3 drugs ) , anaplasia and whether initially treated on national wilms ' tumor studies 2 or 315 ) . when there is clinical suspicion , cranial surveillance should be added to routine clinical work - up of wilms ' tumor follow - up to detect intracranial masses in a timely manner . combined aggressive therapy ( surgery+radiotherapy+chemotherapy ) should be applied whenever it is possible for both better survival and palliative aspects .