Extrapulmonarysmallcellcarcinoma(EPSCC)isarareneoplasmcomprising2.5%to5%ofsmallcellcarcinomas(SCCs).BladderSCCisthemostcommonsiteofgenitourinarytract.PrimaryrenalSCCisextremelyrare.WereportacaseofprimarySCCofthekidneywhichisrarelyreportedintheurinarytractandpresentsanaggressiveclinicalpicture.A59-year-oldfemalevisitedaurologicclinicwithcomplaintofpersistentleftflanksoreness10yearsafterundergoingrenaltransplantation.Abdominalcomputedtomographyshowedaleftrenalpelvistumor.Afterthepatientreceivedleftnephroureterectomywithbladdercuffresection,herpathologyresultsshowedSCC.Aftersurgery,shereceivedadjuvantsystemicchemotherapy,andherrecoveryhasbeenuneventfulasof8months.PrimaryrenalSCCpresentswithanadvancedtumorstageandashortmediansurvivalperiod,thereforeearlyinterventionandclosefollow-uparerecommended.
