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BACKGROUND: Paediatric renal cell carcinoma (RCC) is a rare neoplasm which differs significantly in its clinico-pathological behaviour from the adult variant. The clear cell variant constitutes a relatively small histological subset of this neoplasm. CASE REPORT: We present a very unusual, pathologically proven case of clear cell variety of pediatric RCC which showed invasion into the pelvicalyceal system with contiguous extension up to the urinary bladder. Such a novel manifestation of paediatric RCC has not been described previously in literature. A relevant review of literature is included. CONCLUSIONS: The aggressive biological behaviour of the paediatric RCC in our case and the consequent atypical imaging findings are distinctly unusual. These findings may represent a new aggressive variant of this rare neoplasm. The radiologist and clinician should be aware of these novel manifestations of paediatric clear cell RCC.